Rum—Distinction of Genuine and Artificial (1909)

[10/24/16] Yes, I found Micko’s original papers and they had a lot offer even though they were somewhat expanded upon by Arroyo. No, I will not share them yet because they hold all the secrets to the future of the new distilling scene.]

Jamaica Rum—Distinction of Genuine and Artificial.—Real Jamaica rum contains certain aromatic bodies which do not occur in European potable spirits nor in fictitious rum. R. Micko finds that if 200 Cc. of the spirit and 30 Cc. of water are distilled into seven fractions, each of 25 Cc, the first two or three fractions will contain alcohol and the esters of formic and acetic acids. The fractions following will have a characteristic odor when the rum is artificial. With genuine Jamaica rum the typical aroma occurs in the fifth and sixth fractions. Not only can a trained sense of smell and taste differentiate between genuine and spurious rum by this test, but can even detect a mixture of one with the other.—Pharm. Journ., Feb. 13, 1909, 188; from Chem. Techn. Beport, J2 (1908), 675.

This little blurb proved popular back in the day and was published in many other places. R. Micko who the passage mentions was a well cited fermentation chemist working for the French islands.

I chose to highlight this small fragment of the rum history because it parallels some ideas that are in my Distiller’s Workbook. Basically, we can learn a lot about spirits by chopping them up. If we suspect a rum of containing significant amounts of sugar, we can simply dehydrate a few ounces of that rum and weigh the non-volatile fraction to see what’s left over. It can often be a $2 experiment. If we suspect there are non-sugar cane (or barrel) derived flavoring additives, simple distillation and separation into fractions could add weight to the argument. The sophistication of rums back then may not have been as complex as it is today, but if a rum was finished in a barrel that formerly held something like orange liqueur, the test might make that very apparent relative to the same test performed and compared fraction to fraction on genuine rums.

Cutting up and comparing spirits fraction by fraction should become standard practice in new distilleries. If we know where the congeners lie and how to manipulate their values we may be able to sculpt or blend spirits in ways people do not think possible without GCMS or being a savant.

Last year I looked at a set of papers, The Flavor Components of Whiskey, which used an off the shelf, but sort of complicated, fractional vacuum distillation technique to cut up a whiskey along various lines of its volatility (then they analyzed the fractions). This was an extremely high fidelity way to do it, but the above 1909 method employing simple atmospheric distillation in glass with no (specified) reflux column is likely to tell enough to the low involvement low budget explorer.

The Flavor Components of Whiskey confirmed my earlier hypothesis that the salient characteristics of barrel aging was the least volatile, if barely volatile, and could justify weird renderings like my DIY barrel proof Overholt or the infamous Fernet 151.

Aficionados have accused many rums on the market today, like the Pyrat rums, of fooling around and have requested stricter labels to create transparency. I’m against that. What I would love to see is some old school competitor analysis that raises flags and is published in popular forums. I feel such published questions of authenticity backed up by scholarly work are enough to be bound to that label and negate any need for overly strict legal transparencies. I see it as the connoisseurial way.

Drinking is safe enough and governments do an amazing job of protecting us from toxic congeners like lead, methanol, and ethyl carbamate. We don’t need governments to protect us from bad art and the many GRAS spirit additives that obfuscate any sense of place. We can do it ourselves. I’m completely for the pursuit of a sense of place and other ideas like authenticity, but I want to go on a journey, confer with others, sort experiences, and find it myself.

I could say more about the finer points of this technique and maybe give anecdotes of performing it brand for brand. Maybe I will in the not so distant future.

The Micro-Organism of Faulty Rum

This strange book came across my desk as I was looking for scientists that worked on New England rum: The Micro-Organism of Faulty Rum (1898) What a title! Its a whole book? (64 pages) What the hell is this all about? (There is a big punchline at the end, but if you are really lazy feel free to scroll to the very end and read backwards.)

The book was referenced in Cane Sugar: A text-book on the agriculture of the sugar cane, the manufacture of cane sugar, and the analysis of sugar house production together with a chapter on the fermentation of molasses by Noel Deerr, sugar technologist at the experiment station of the Hawaiian sugar planter’s association, 1911.

So back in 1898 this husband and wife team of researchers were finding micro organisms in rum. This confused a lot of people so they took their samples to another more esteemed micro biologist, Emil. Chr. Hansen of the Carlsberg laboratory. Dr. Hansen “confirmed our results, though not our conclusions in their entirety […]”. It seems like Hansen says, yes you’ve got micro organism in your rum but I don’t think they grew there.

Lets back track to Noel Deer:

“Faulty Rum.—By faulty rum is meant a spirit which on dilution with water becomes cloudy and throws down a deposit. The causes to which this behaviour are attributed are:—The presence of caramels soluble in strong and insoluble in dilute spirit; the presence of higher fatty acids, due to care less distillation, which are precipitated on dilution; the presence of terpenes extracted by the spirit from the casks; the presence of a micro organism capable of life and reproduction in 75 per cent, alcohol; the latter view was brought forward by V. H. and L. Y. Veley who named the supposed organism Coleothrix methystes and stated that it is extremely resistant to ordinary methods of destruction, survives desiccation, is air borne, and both aerobic and anaerobic; in certain of their publications the organism is described as multi-Inlying and living actively in 75 per cent, rum and in other places as merely surviving in spirit. The whole of the results of V. H. and L. Y. Veley were challenged by Scard and Harrison, who were unable to obtain any of the effects noticed by the Yeleys. They found, however, in Demerara rums remains of organisms similar to the one in question, and were of opinion that fauiltiness in rum was due to the first three causes mentioned above.”

So these researchers that took it upon themselves to investigate the Veley’s results only found questionable micro organisms in Demerara rum. Presumably they tried all types of rum?

Noel Deerr goes on a little more with his own experiences and describes finding fungal growths that possibly were in barrels and survived the journey to England:

“The writer thinks it quite possible that masses of the organism, to the existence of which he gives credence, have found their way into casks and puncheons, and have thus been present and alive on arrival in England, but does not think they can be called the cause of faulty rum.”

From the Introductory Chapter I:

So the problems pretty much only afflict the Demerara rums of Guyana. And there was enough interest in the problem to interest the Agricultural Committe of Guyana to spend time figuring it out.

From Mr. Harrisson, the appointed Agricultural Committee investigator:

The text goes on to report the private nature of correspondences probably regarding conspiracy theory that no one wanted to get out to the public because they would shatter confidence in the rums diminishing their value.

Its starting to get complicated. They pretty much try and salt out any chemical compounds like fatty acids that could be causing the problem. What is left are organic bodies.

Back then they were probably thinking they were in x-files territory. If over proof rum can’t kill it, what if it escapes and eats our flesh? Its also coming from deep within the jungles of the Demerara river.

Did they think it was dividing actively because they assumed it entered the rum as a single spore and grew from there into significance? And if they were able to grow it further, were they not making a mistake and growing something else similar local to their environs. We’ve recently found new ways bacteria can protect itself, such as with trehalose, and there are some forms thought to be near immortal that can grow weird protective shells that survive all sort of extremes like the vacuum of space.

So they’ve never been there. The Vely’s eventually show some statistics of faulty rum, which was first noted as a phenomenon sixteen years prior. Its hard to draw conclusions whether every fault was related to bacteria. The faults could have been due to the other categories like excess fatty acids and issues with caramel.

The samples keep coming and there are just as many that are faulty for ones that are not.

So I interpret this as they can’t get anything to grow in the rum. What they then try is to grow bacteria out of rum then add it to rum to see if they can get faulty results which is the clouding.

They go on to shoot down Harrison and the work done in the tropics for not being rigorous enough and probably making obvious errors. This is their grounds:

Death of the microbes in the rum can still cause clouding. But how did they get there?

“alleged bacterium”. At some point in time there was probably serious name calling.

They find micro organisms in the caramel used for coloring. But they are not using fresh caramel, they are using caramel that made the trip from Guyana to England.

They examine Liverpool water and find no micro organisms.

Basically it is not louching because of excess free fatty acids because some not faulty spirits had more free volatile acids than faulty spirits. Though this does not take into account the exact distribution of types of fatty acids.

They get into turbidity, opalescence, and florescence.

Harrison’s resin theory where turbid compounds were extracted from the wood is disproved because all barrels from all firms were made from the same lumber.

They break out the petroleum spirit.

They break out some optics theory.

I promise we are getting closer to the punch line.

Everything is getting complicated:

There are shreds of possibility to this:

This quote is taken out of context:

Fearing x-files type shit, they tested on animals:

Some of many closing remarks in the conclusion that they acknowledge might work against their findings:

And then they name it:

This is where they kept the beast:

Behold the beast!

Orgy of beasts:

Let’s put this all to rest and reference IRS chemist Peter Valaer, 1937:

raw meat

Long ago I tried this so you don’t have to.

Rum Miscellany

We are closing in on the capstone paper of the last 150 years of rum, the most malleable of spirits. I thought I’d share some of the interesting miscellany I’ve come across and probably later on there is going to be some stragglers that are still out on inter library loan.

An interesting article was Industrial Alcohol by James Doran. He starts with a history of industrial alcohol in America which gives a small time line and lets us know how sophisticated producers were in America early on.

Pure Products is an interesting series and if you search through it you can find wild things about alcohol and other early agricultural products. Page 578 has a great article on the Alcohol Distillation From Molasses by George M. Appell and focuses on building efficient fuel ethanol plants in the Caribbean. Something surprising is that scientists thought all gains and real need for expertise in production was on plant design and fermentation chemistry. The actual handling of the still which we fetishize today was very simple if not trivial.

Another Pure Products article on page 30, Distillery Practice and its Scientific Control by Dr. H. Lange. This article spends time looking at acidity at various stages of fermentation which people were realizing was of particular importance. I don’t think pH had become a thing yet (this was 1917?) and titration was still the method of measurement. I think I should upgrade the significance of the article and look into who Dr. H. Lange was.

History of the Coconut Tree (1825) from the Boston Journal of Philosophy and the Arts. The article spends a nice amount of time describing Arrack.

This 19th century Journal of Banking article was interesting:

“For my part,” said Tom, “I look upon New England rum as the best standard of value.”— Hereat I laughed : but Tom told me not to laugh, but to listen, while he compared certain qualities of New England rum with those qualities of gold and silver which, according to the Political Economists, fit them to perform the functions of standards and measures of value.
“In the first place,” said Tom, “the demand for New England rum, is universal and incessant, the efforts of the Temperance Societies to the contrary notwithstanding; and the supply exactly equals the demand. Every Political Economist will admit that the laws of supply and demand, affect New England rum in the same way that they affect gold and silver.

“In the second place, it (New England rum) is divisable into extremely minute portions, and capable of reunion without any sensible loss of weight or value. This divisibility and capability of reunion, Say, in his Political Economy, places first in his enumeration of the qualities of gold and silver which fit them for the purposes of money. But every man knows that any given portion of New England rum can be divided and reunited with much more ease than any given mass of gold or silver.

“The exact strength, and consequently the purity, of New England rum, can readily be ascertained by means of a hydrometer. To ascertain the fineness of gold and silver, we have to resort to the troublesome process of assaying.

“Time, weather, and damp, says Say, have no power to alter the quality of gold and silver.— Neither do they injuriously affect New England rum. It rather improves by age. You can carry it into any climate. In very cold regions, it is indeed liable to be frozen; but then it can be cut into blocks, and serve very conveniently the purposes of a circulating medium. In this form, I have no doubt, it would be highly prized by the Esquimaux. If the Abyssinians use salt bricks, as money, why should not the Esquimaux use little blocks of frozen rum?

“Molasses was once a kind of secondary standard of value with our Yankee boys. Nothing used to be more common with them than to say that they had got for their produce,’half cash and half molasses,’ meaning thereby, not molasses literally, but various commodities, of which they made molasses the general representative. In like manner, New England Rum was a kind of standard of value, and even currency, contributions for public objects being made in that medium. Of this, History affords us a remarkable example. When the New Hampshire troops were preparing to join the forces under Gen. Gates, contributions were made to defray their expanses, and among others, Governor Langdon subscribed a large sum. But how did he pay it? In gold and silver? No. He was not so foolish as that. He knew that gold and silver could be neither eat nor drunk; and, like a sensible man, he rolled out his four or five hundred barrels of New England Rum. With these, supplies for the troops were procured. And to his rum contribution we are, at least in part, indebted for the glorious victory of Saratoga, and the consequent capture of Burgoyne and his forces.”

Pretty well for Tom. When he had done, I told him that he ought to write to Professor
of the University of Pennsylvania, and Professor of the College of South Carolina. As one of them had made the discovery that “the whole utility of specie as money is its power of creating a confidence,” and the other the no less notable discovery that “money is not wealth,” I could not doubt they would duly appreciate his discovery of a new standard of value. Tom said he would think of it. He had his fears, that, if he wrote to those gentlemen, they would seize hold on his theory, dress it up anew, and give it to the world as their own, thus robbing him of honors justly his due.

This Jamaican rum factory designed in Berlin, depicted in Industrial and Manufacturing Chemistry, Volume 1 by Geoffrey Martin features a shower to cool the fermenting vats. I wonder if this was ever built because the shower seems like an inefficient idea, but if you consider the tax structure where Jamaican rums were taxed at many multiples their wholesale, there were giant incentives to improve quality. There was plenty of room to sell flavored rums at a much higher price without making a that big a different to the after tax price.

I’m dying to get this doctoral thesis by Ian Leighton Thompson: Studies on the maturation of Jamaican rum. The abstract is here.

H. W. Wiley Tells of Rum

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I did not initially think there would be anything good to reference in H.W. Wiley’s 1919 text, Beverages and their adulteration, origin, composition, manufacture, natural, artificial, fermented, distilled, alkaloidal and fruit juices, but it proved really interesting. Wiley was a Bureau chemist who at one time employed Harris Eastman Sawyer who I have alleged was the architect of the modern New England rum style. Sawyer unfortunately died in 1911 so he probably only worked for Felton & Son’s of South Boston for ten years.

When considering Wiley’s explanation of rum, consider his bibliography when he gets to his present day. He and Sawyer were more in the scene of American analytical chemists as opposed to the scene of far flung international sugar chemists. Wiley also had the benefit, no doubt, of hearing all about rum from his time with Sawyer.

H.H. Cousins, Jamaica’s Director of Agriculture, is referenced, and when describing the present, Wiley spends far more time on Jamaica than he does on New England or the rest of American production. Despite discussing Jamaica, and discussing bacteria, Wiley makes no reference to the difference between budding or fission yeasts that were mentioned in Jamaican rum research 10 years earlier.

The references to Colonial America are interesting and there is definitely a point in rum’s domestic progress (which I think is Sawyer’s arrival) that divides the colonial era from the next era defined by scientific investigation. Wiley gives the feeling that he sees the current state of rum, despite prohibition, being completely modern. He looks backwards with as much distance and we look back on him, though we really haven’t come very much further. Or have we?


Definition.—Rum is an alcoholic beverage distilled from the unrefined fermented products of the sugar cane. The term “rum” is often given as synonymous with all distilled liquors, much as brandy and whisky are used in the same sense. Distinctively speaking, rum is applied only to a spirit distilled from molasses, or from sugar cane products. The sugar cane juice may be fermented directly, or the products of manufacture, notably the molasses, after the separation of a crop of sugar, are used particularly for this purpose. In fact, for all practical descriptions it may be said that rum is an alcoholic distillate derived from the fermented molasses of sugar cane. Rum may be made wherever sugar cane is produced, but experience has shown that there are certain localities, as in almost every other instance of this kind, in which the product is of greater value than in other places.

Rum is one of the oldest and most widely known of distilled alcoholic liquors. Its particularly peculiar flavor and aroma come from the aromatic volatile bodies naturally present in cane juices, produced in the course of manufacture, or formed during the distillation and aging of the product. It is evident that very little volatile aromatic substances can remain in molasses, by reason of the fact that in the making of molasses a very high temperature is reached, especially if the sugar cane juices be boiled in an open kettle. If a vacuum pan be used the heat of boiling is very much lower but the volatility of the bodies therein is correspondingly increased by the diminished pressure. Nevertheless, all molasses has that fragrant aromatic odor peculiar to this sugar cane product and this fragrant odor is preserved to a large extent to the distillate. Rum, as is the case with other distilled liquors, improves greatly on keeping in wood, and both for beverage and medicinal purposes it is highly important that the rum be well aged. The Act of Congress prescribing a term of four years of storage for distilled spirits bottled in bond is based largely on the fact that during the first four years after manufacture the improvement in the quality of distilled spirits is extremely rapid. In a country where the temperatures in summer are equal to those of the United States, the ripening of the distilled spirits makes great progress in this time, though it is by no means complete. The term “old” probably should be applied to a rum much older than four years, although at the end of four years the rum has assumed quite a fragrant and attractive character. Among the localities which produce rum of the highest character may be mentioned the islands of the West Indies, especially Jamaica.

Jamaican rum is probably the most famous of the rums of commerce. Rum is made in almost every country where sugar cane grows, and very largely in countries where it does not grow, as for instance, New England, where the rum industry was established more than a century ago and where it has flourished up to the present time.

Character of the Raw Material.—The molasses which is produced in Louisiana has not been used very extensively there for the manufacture of rum, because it is not sufficiently aromatic, or because the refinements of manufacture have extracted from the molasses too much of its saccharine contents to make it a suitable source for the manufacture of rum. Moreover, it may be said that the use of the fumes of burning sulphur in treating the juices of the expressed sugar cane tends to render the molasses unfit for the manufacture of rum. It would be impossible to make a rum, which would have any character at all from black strap, a lowgrade molasses, or molasses in which the content of sulphur dioxide had been increased to a very large amount by the successive concentrations and extractions of the sugar therein contained.

Manufacture.—The manufacture of rum does not differ in any essential particular and principle from the manufacture of other distilled liquors. In the case of rum there is one difference which is quite marked between that industry and the whisky or spirit industry in general. There is no starch which must previously be converted into sugar before the fermentation takes place. Inasmuch, as the cane sugar which remains in the molasses is not acted upon directly by the ferments, it is important that it should be changed into invert sugar before or during the process of fermentation. Fortunately, the yeasts which are used in the fermentation secrete a diastase which is very active in converting cane sugar into invert sugar. Hence, it is usually not found necessary to convert the cane sugar into invert sugar by treatment with an acid or otherwise before the fermentation begins. As a rule, the invertase secreted by the yeasts is quite sufficient for the purpose mentioned.

Time of Fermentation.—The period for the fermentation of rum is longer than that for the manufacture of whisky, and this is recognized in the regulations, which allow a longer period for fermentation in a distillery surveyed for the manufacture of rum than when surveyed for the manufacture of whisky or alcohol.

While, as is said above, molasses may be considered the base supply for rum, other materials derived from sugar cane are used in many countries in its preparation, wholly or in part. The skimmings which are taken from the boilers of the old open-kettle processes of manufacture are often mixed with the molasses, and there is also found employed in the manufacture of rum the counterpart of the sour mash process of making whisky. In other words, a portion of the residue from the previous distillation, known in some countries as “dunder,” is added to the mash. The rum which is produced wholly from refuse molasses is of a very inferior character, and the same term is applied to it in many countries as was applied to the low-grade whisky made in this country, namely, “nigger rum.” [Wiley was probably a disgusting racist person. I think this really shows the level of his integrity. The only other place I have seen this language was Herstein & Gregory, 1935. Beyond the racism there are other parts of Wiley’s writing that make you question his integrity as a researcher.]

Dunder.—The nature of “dunder” may be described as follows: When the fermented mash from which the rum is to be made is placed in the still, it contains practically all of the yeast cells, living and dead, which aided in or were produced during fermentation. The warming of the fermented material in the still produces a rapid extraction of the soluble materials from the yeast cells. These soluble materials, as is well known, are of the nature of diastases or enzymes. This whole mass, after the removal of the alcohol by distillation, is naturally concentrated and the extracts are in a more usable form than they were before. This material, consisting of numerous mineral matters and other substances, as well as the remains of the yeast cells, forms an excellent food for the nourishment of the new yeast cells of the succeeding fermentation. Naturally, the “dunder” itself does not afford any alcohol, but it stimulates the growth of the yeast, so as to produce a larger yield and of a finer character, provided the quantity of “dunder” employed is not too great.

It must not be forgotten that not only does this residue of the fermentation of the rum contain valuable qualities, but it also has some disadvantages. The “dunder” is very apt to be infected with bacteria, some of which are not killed during the process of distillation. Especially is this true of the bacteria which are produced from spores. Inasmuch as the constituents of this residue are an excellent food for yeasts, they also become likewise a most excellent food for bacteria.

The development of bacteria may interfere very seriously with the succeeding fermentations and introduce elements of activity which tend, or may tend, to produce a product of an inferior quality. Hence, as in the case of using sour mash, attention must be paid to the process of fermentation, in order that no undesirable strain of bacterial or yeast life may be produced.

Manufacture of Jamaican Rum.—Attention has already been called to the fact that rum of most excellent quality, perhaps the most famous of all rums, St. Croix alone excepted is made in Jamaica. Various grades of rum are made in this island, according to the nature of raw materials used and the processes of fermentation and distillation employed.

Varieties of Rums.—In Jamaica a distinction is made between the ordinary “clean” or Jamaican rum, and the very highly flavored product, which by way of distinction is known as “German Rum.” Various theories have been advanced to account for the difference between the “clean ” rum or the ordinary rum, and the highly flavored rums which are produced in this island. The common, belief, as has been expressed, is that the flavoring qualities which distinguish rum from other distilled spirits are peculiar to the sugar cane. They either exist naturally in the products of the cane, or they are produced from pre-existing sources during the processes of fermentation. The essential chemical difference between the ordinary rum of the Jamaican product, and the highly flavored rum, as might be inferred, is in the quantities of esters, or ethers, which they contain. The highly flavored rum contains considerably larger quantities of these ethers than that of the ordinary character; in fact, the quantity is almost twice as great.

Manufacture.—The common rum of Jamaica is made in a very simple way, which may be described as follows:

Molasses is used as the base raw material, and in the regular operation of the distillery “dunder” is used in the fermenting tanks, as has already been described. The skimmings which come from the open kettle used in boiling the product are also added to the fermenting tank. The skimmings are supposed to be particularly valuable by reason of increasing the acidity of the fermented mash. Some manufacturers allow the skimmings to stand in tanks until they become sour, while others allow them to trickle through cisterns over cane trash, which produces a rapid oxidizing effect.

In the manufacture of higher flavored rums an attempt is made to produce a greater etherification, and, consequently, a larger production of aromatic substances due to the action of microbes. These additional flavors cannot be regarded as coexisting in the sugar cane, but they are the product of bacterial activity exercised on the original materials. The two organisms which are most active in this respect are the bacillus butyricus and the bacillus amylobacter, and other forms allied thereto. These bacteria are very common and exist frequently in soil and are not difficult to introduce into fermenting solutions. They are mostly produced from spores and are difficult to destroy by the ordinary processes of sterilization.

The bacillus butyricus is an anaerobic organism and it will not develop well unless it is grown out of contact with oxygen. For this reason, in pure cane juices its action is not at all vigorous. Where the cane sugar has been more or less inverted, this bacillus acts with much greater vigor, especially if some albuminous matter be present. The extract of yeast cells adds very much to the activity of these organisms, and in this we see a scientific reason for the use of “dunder.” The exclusion of the air from the fermenting tank presents practical difficulties in the production of the maximum activity of these anaerobic organisms. Before the aid of scientific investigation was placed at the disposal of the rum maker, he found that to produce very highly flavored rum he would have to add some material to the fermenting mass, which contained, although he did not know it, a considerable quantity of nitrogenous matter, and this was applied from the “dunder” of the preceding fermented mass. The utilization of these special ferments is another reason why the period of fermentation for rum must be longer than that for the manufacture of whisky or spirits. These bacteria are not of quick action; they move slowly and they require some time to produce their full effect. Hence, the period of the rum production may be well above 72 hours without going too far.

There is a popular impression in Jamaica that good rum cannot be produced in a modern sugarhouse, using modern machinery. While some authors doubt the truth of this belief, it must be borne in mind that modern methods, which take away increasingly large quantities of sugar, must, of necessity, diminish the fermenting value of the molasses, and add thereto, proportionately, very much larger quantities of foreign matters than in the style of molasses formerly made. It is perfectly reasonable to suppose that improved machinery would result in a depreciation in the character of the product.

Further Divisions of Rum.—Jamaican rums are further divided from a commercial point of view, into three classes, namely:
1. Rums for home consumption.
2. Rums for export to England.
3. Rums for export to the continent of Europe.

Although rum is one of the principal products of Jamaica, fortunately it is not consumed in very large quantities at home. The statistics show that the local consumption of rum does not much exceed a gallon per head per annum. The citizen of Jamaica cannot be regarded as an inveterate rum drinker. While this is regretted from the point of view of inland revenue, it is a matter of congratulation from the point of view of temperance in the use of all things.

In Jamaica, as in other countries, the introduction of the manufacture of pure spirit has opened the doors for mixing native rums with neutral spirit, and as this is cheaper than making rum in the old-fashioned way, it is not at all surprising that the consumption of these mixed articles has practically driven the consumption of old-fashioned straight rum out of the market. As has been stated by Mr. H. H. Cousins, Government Analyst for Jamaica.

The high-class trade in old rums of delicate softened flavor, which were formerly so highly thought of by the planters and moneyed classes, has largely disappeared, and it would probably be most difficult to obtain a choice mark of an old rum, which has not been blended, from any spirit merchant in Jamaica today.

In regard to the second class, which is intended for shipment to England, it may be said that the same manipulations during the last few years were tried with this class. To such an extent was the manipulation carried, especially after reaching England, that the Jamaican Government sent a special representative, Mr. Nolan, to London to protest against the adulteration of Jamaican rum and see if he could not re-establish the trade in the genuine article. Mr. Cousins refers to the rums of class two, as follows:

The rums of the class to which I now refer, and which constitute the bulk of the rum exported from Jamaica, represent the type of spirit which Mr. Nolan is seeking to advertise, and to protect from fraudulent adulteration, and from the competition of spurious Jamaica rum in the United Kingdom.

The rums of this class are produced by a slower type of fermentation than those intended for the local trade. Some of the best varieties are produced by fermentations in ground cisterns, slightly flavored by the addition of some soured skimmings to the fermented materials. These rums are very rich in ethers, being hardly less than 300 parts of ethers per 100,000 parts of alcohol, and sometimes a great deal more.

Class three rums are intended for consumption on the continent of Europe. The trade in Jamaican rum has been long established on the European continent. This trade has largely declined in recent years, and is, doubtless, due to the adulteration of the article with molasses spirit and other substances, which so depress its character as to make the beverage unpopular. Another reason which has tended to diminish the consumption of Jamaican rum is the extremely heavy duty imposed upon it in Jamaica. This, in connection with the lower rates of duty on alcohol, has rendered the competition of the artificial with the imported article, even with its fine flavor, very keen.

The rums exported to Europe are commonly those already described as German-flavored rums. Not only are these rums treated as has already been described, with “dunder” and under special circumstances, but the period of fermentation is very much prolonged, reaching sometimes as high as 15 or 20 days. The fermentation takes place slowly, under very acid conditions, the acidity being produced by the addition of soured skimmings, or by the slow process of fermentation to which the mass is subjected.

If the ordinary rum shipped to England may be said to contain about 300 parts of ethers to 100,000 parts of alcohol, the German flavored rums will contain practically double that amount, namely, from 600 to 700 parts. It is readily seen that they are very aromatic and are considered the very highest flavored rums of commerce. Some of these very fine rums have been found to contain as high as 1,500 parts of ethers per 100,000 parts of alcohol. These ethers are those of the coordinate alcohols, namely, acetic ether, derived from ethyl alcohol, and the ethers derived chiefly from the higher alcohols, such as butyl, propyl, and amyl.

Differences in Flavor.—All of these three classes above mentioned vary in flavor. It is said that there are no two plantations in Jamaica which produce rum of the same flavor. The output of rum from each place is influenced by the peculiar bacterial flora of that place, and by the methods employed in fermenting and distilling.

Rum is, of all kinds of distilled alcoholic beverages, the most fragrant, and makes the greatest mass effect upon the olfactory nerves. Only connoisseurs of the highest character can pick out the shades of flavor to a certainty, but no one would be misled in respect to the character of the goods, as a rule, even if he were not a connoisseur.

It is a material of this character, so highly flavored, which is so valuable in the stretching of rums; that is, by mixing them with spirits made from any given source, and thus using the genuine article merely as a flavor to the whole mass. The legitimate trade in rum has almost been destroyed, it may be said, by this system of admixture and adulteration.

The above data show in striking contrast the difference between the “common” or “clean” rums of Jamaica, and the flavored rums or those made carefully with “dunder.” There is little difference, as is seen, in the alcoholic strength, the salts, the total acids, the higher alcohols, the furfurol, and the aldehydes; the great difference is in the volatile acids and the esters. It is easy to see that the flavoring matters must belong chiefly to those two classes.

Rum in Guadeloupe.—The French name “Rhum,” and also the name “Taffea” is applied to the alcoholic products obtained by the fermentation and distillation of the juice of the sugar cane, and of the molasses produced in the factories making sugar cane, in Guadeloupe. The name “rhum” in this island is particularly applied to the product obtained by the distillation of the juice itself, and the name “taffea” to the product having molasses as its origin. These different usages of the term are not absolute, and especially in France the term “rhum” is applied to “taffea” which has been stored some years in the cask. Unhappily, in France it is usually mixed with industrial alcohol before it reaches the consumer, or worse still, some artificial product is sold under its name, a product made with artificial essences and with industrial alcohol and the whole colored with caramel.

The true “rhum,” that is, the beverage made from the juice of the sugar cane in Guadeloupe, never reaches France, although its manufacture is a very important item in the island. It is practically consumed in the home of its production. The “rhum” made from the sugar cane juice, when kept for several years in wood without the addition of anything whatever, acquires a bouquet which approaches in excellence that which is acquired by old brandies.

The total production of “rhum” and “taffea” in Guadeloupe is not very great, and as has already been indicated very little of it, if any, is exported. More perhaps of the variety known as “taffea” is exported than of the true “rhum.” The quantity of “taffea” produced is also larger than that of “rhum.”

Other varieties of rum are also made in Guadeloupe, for instance rum made from the boiled cane juice. In the manufacture of this drink the juice of the cane is heated in the boiler in such a way as to boil violently for some minutes. Its density is then considerably increased, the scum is carefully removed and it is allowed to cool. It is diluted with water in such a way as to bring it back to its original density. Finally, this product is taken to the cisterns of fermentation and treated in the ordinary way. Evidently the object of this boiling is to sterilize the juice, thus destroying the adventitious ferments, and at the same time purifying it to a certain extent by removing certain quantities of the matter coagulable by heat and commonly known as “skimmings.”

There is still another variety, made in Martinique, from what is known in that country as “gros sirop.” This molasses is obtained in the manner of the old-fashioned open-kettle molasses, being the dripping from the sugar cane juice boiled over a naked fire in an open vessel until it reaches a crystallizing density. The quantity of sugar made in the island in this way at the present time is almost nil, and hence the amount of rum thus produced is inconsiderable.

In the manufacture in Guadeloupe “dunder” is also used in the fresh fermentations, but the name of it in this island is “vinasse,” namely, the residue of the distillation of the preceding fermentation, in order to produce the rum. This vinasse is very strongly acid and contains usually only traces of sugar, but has a dry residue amounting from 35 to 40 grams per liter. The ash is rich in phosphoric acid and potash. It serves, as has already been stated, for the nourishment of the yeasts, especially in the addition of certain quantities of nitrogenous matter and of mineral substances such as phosphoric acid and potash, which the yeasts require for their proper nourishment.

Distillation in Guadeloupe.—The distillation in Guadeloupe is carried on very much in the same manner as that of Cognac in France. The apparatus consists of practically three parts: the heater in which the fermented mash is raised to a high temperature by the vapor escaping from the still; the still itself, which is the ordinary pot still; and the cooler, which is the ordinary worm surrounded with cold water.

Rum in Demerara.—Rum is also made to a considerable extent in Demerara. Inasmuch, however, as the principal product of the sugar cane is sugar, the raw materials do not have such a high character as those used in Jamaica and in other islands where the process of extraction of the juice for sugar-making purposes is less perfect. The rum made in Demerara is distinctly inferior to that produced in Jamaica and Guadeloupe, St. Croix, and other West Indian countries. Very little, if any, dunder is used in Demerara. The fermentation is produced solely by the added yeasts and is carried on much more rapidly than in Jamaica and Guadeloupe. Moreover, the Demerara rum is often, or largely, produced in chamber stills, or rectifying columns, which is never the case in Jamaica, where only pot stills are employed. This is another reason why the Demerara rums average more nearly the character of alcohols in proportion as they depart from the true character of rums.

Early History of Rum in New England.—The early history of rum in New England is set forth in a work by Alice Morse Earle, entitled “Customs and Fashions in Old New England,” published by Charles Scribner’s Sons in 1893. On page 174 the author says:

Aqua-vitas, a general name for strong waters, was brought over in large quantities during the seventeenth century, and sold for about three shillings per gallon. Cider was distilled into cider brandy, or apple-jack; and when, by 1670, molasses had come into port in considerable quantities through the West India trade, the forests of New England supplied plentiful and cheap fuel to convert it into “rhum, a strong water drawn from the sugar cane.” In a manuscript description of Barbadoes, written in 1651, we read: “The chief fudling they make in this island is Rumbullion alias Kill-Divil—a hot hellish and terrible liquor.” It was called in some localities Barbadoes liquor, and by the Indians “ahcoobee” or “ockuby,” a word of the Norridgewock tongue. John Elliot spelled it “rumb,” and Josselyn called it plainly ”that cussed liquor, Rhum, rumbullion, or kill-devil.” It went by the latter name and rumbooze everywhere, and was soon cheap enough. Increase Mather said, in 1686, “It is an unhappy thing that in later years a kind of drink called Rum has been common among us. They that are poor, and wicked too, can for a penny or two-pence make themselves drunk.” Burke said, at a later date, “The quantity of spirits which they distill in Boston from the molasses they import is as surprising as the cheapness at which they sell it, which is under two shillings a gallon; but they are more famous for the quantity and cheapness than for the excellency of their rum.” In 1710, and fifty years later, New England rum was worth but three shillings a gallon, while West India rum was worth but two-pence more. New England distilleries quickly found a more lucrative way of disposing of their kill-devil than by selling it at such cheap rates. Ships laden with barrels of rum were sent to the African coast, and from thence they returned with a most valuable lading—negro slaves. Along the coast of Africa New England rum quite drove out French brandy.

The Irish and Scotch settlers knew how to make whiskey from rye and wheat, and they soon learned to manufacture it from barley and potatoes, and even from the despised Indian corn.

The drinking of compounded liquors was also practised in old New England, as shown by the following extract from page 178 of this work, beginning:

Flip was a vastly popular drink, and continued to be so for a century and a half. I find it spoken of as early as 1690. It was made of home-brewed beer, sweetened with sugar, molasses, or dried pumpkin, and flavored with a liberal dash of rum, then stirred in a great mug or pitcher with a red-hot loggerhead or bottle or flip-dog, whch made the liquor foam and gave it a burnt bitter flavor.

Landlord May, of Canton, Mass., made a famous brew thus: he mixed four pounds of sugar, four eggs, and one pint of cream and let it stand for two days. When a mug of flip was called for, he filled a quart mug two-thirds full of beer, placed in it four great spoonfuls of the compound, then thrust in the seething loggerhead, and added a gill of rum to the creamy mixture. If a fresh egg were beaten into the flip the drink was called “bellowstop,” and the froth rose over the top of the mug. “Stonewall” was a most intoxicating mixture of cider and rum. “Calibogus,” or “bogus” was cold rum and beer unsweetened. “Black-strap” was a mixture of rum and molasses. Casks of it stood in every country store, a salted and dried codfish slyly hung alongside—a free lunch to be stripped off and eaten, and thus tempt, through thirst, the purchase of another draught of black-strap.

A terrible drink is said to have been made popular in Salem—a drink with a terrible name—whistle-belly-vengeance. It consisted of sour household beer simmered in a kettle, sweetened with molasses, filled with brown-bread crumbs and drunk piping hot.

In a work published in 1890 entitled “Economic and Social History of New England,” by William B. Weeden, it appears that distillation began in Salem as early as 1648. On page 186 we find the following:

Emanual Downing writes that Leader has cast the iron pans to be used in the process. Downing began distilling in Salem this year. Frequent commerce with the West Indies carried out unmerchantable fish to be exchanged for molasses.

On page 188 it is stated:

Rum was much used by the common people, and malt liquors were the favorite drink of the English colonists. The native New England beverage was cider and the presses began to work about 1650. Much barley had been raised in Plymouth. The many malthouses were not so common after this.

In 1686 the Southern part of the Colonies had commenced to buy rum from New England, as stated on page 376. In 1690 it is stated (page 416), “Cider and vinegar corrected the West Indian sugar and molasses always coming in; that is, when the molasses did not evolve itself into the fiery rum. Rum was beginning to be the important commercial factor which it came to be later in the century.”

By 1670, it is stated on page 459:

The West Indies afforded the great demand for negroes; they also furnished the raw material supplying the manufacture of the main merchandise which the thirsty Gold Coast drank up in barter for its poor, banished children. Governor Hopkins stated that for more than thirty years prior to 1764, Rhode Island sent to the Coast annually eighteen vessels carrying 1,800 hhds. rum . . . . . Newport had 22 still houses; Boston had the best
example, owned by a Mr. Childs . . . . . The quantity of rum distilled was enormous, and in 1750 it was estimated that Massachusetts alone consumed more than 15,000 hhds. molasses for this purpose . . . . . The consumption of rum in the fisheries and lumbering and ship-building industries was large; the export demand to Africa was immense.

The adulteration of rum was an early practice. Captain Potter, in 1768, gave directions for the trade on the African Coast, as follows:

Make yr Cheaf Trade with The Blacks and Little or none with the white people if possible to be avoided. Worter yr Rum as much as possible and sell as much by the short mesuer as you can.

Order them in the Bots to worter thear Rum, as the proof will Rise by the Rum Standing in ye Son.

Evidently the Captain was provided with a rectifier’s license.

In 1740, it is stated, page 501:

The most important change in the manufacture of this period was in the introduction of distilleries for rum. Massachusetts and Connecticut undertook the business, but Rhode Island surpassed both in proportion . . . . . The trade in Negroes from Africa absorbed quantities of rum.

The 18th century brought in the manufacture of New England rum with far-reaching consequences, social as well as economical. It was found that the molasses could be transferred here and converted into alcohol more cheaply than in the lazy atmosphere of the West Indian seas.

No Rectification.—In all the references which are made to the manufacture of rum in New England not a single intimation is made that the spirit was ever rectified or mixed with a neutral spirit color and flavor to make a beverage. In fact, the neutral spirit was unknown as a commercial proposition. The stills which were used were the old-fashioned pot stills. It is stated, on page 502, that Mr. Thomas Armory

built a “still-house” in 1722, bringing pine logs 28 feet long, 18 inches in diameter, from Portsmouth for his pumps. In 1726 he orders a copper still of 500 gallons capacity from Bristol, England. The head was to be large in proportion, the gooseneck to be of fine pewter and two feet long, with a barrel in proportion to the whole still.

This shows the character of the still and the nature of the spirit which must have been made therefrom. In the early history of its production there is nothing known of the modern process of rectifying, mixing, adulterating, compounding, coloring and flavoring. In 1659 a hogshead of rum was quoted at 12 pounds, 12 shillings. In 1670 it had fallen to 7 pounds. In 1671 it was quoted at five shillings per gallon. Insofar as can be judged by the early history of these substances, the contention that has been made, that distilled beverages were always rectified, colored, adulterated, mixed and flavored before consumption, does not appear to have any basis in fact.

Morewood, on page 334, of his work, writes of New England rum in the following language:

The rums of New England are considered of good quality, and some deem them not inferior to the best that are produced in the West Indies. In 1810, they distilled in this State 2,472,000 gallons of rum; from grain, 63,730 gallons; from cider, 316,480 gallons, while the breweries yielded 716,800 gallons. Besides this extensive manufacture, much is imported. Geneva is successfully imitated, particularly since the tide of emigration has brought many intelligent men from Holland, who possess sufficient knowledge of this branch of trade, to render the American article equal to that manufactured in the Netherlands. Many of the Irish emigrants distill, in genuine purity, that description of spirits commonly called Innishowen or Potheen, which is no less a favorite on the other side of the Atlantic, than on the shores of Magilligan, or the banks of the Shannon. The following mode of making it at an early period, is thus described by an eyewitness: To a bushel and a half of rye, four quarts of malt, and a handful of hops, were added fifteen gallons of boiling water, which were allowed to stand for four hours. These being increased by sixteen gallons more, two quarts of home-made yeast were thrown in, and in this proportion either a large or small quantity of worts was prepared, which, after being allowed ample time to ferment, was distilled in a simple apparatus. One bushel of rye produced about eleven quarts of weak and inferior spirit, and sold at the rate of 4s. 6d. per gallon. The refuse of these small stills was used in feeding swine.

Description of Rum Making in the Early Part of the Last Century.—An interesting description of the manufacture of rum is found in book written by John Bell and published in 1831 in Calcutta. Mr. Bell describes the manufacture of rum as a part of an article on the manufacture of sugar on a West India plantation. He says his work would not be complete without going into the details of the disposition of the feculencies which form the base of that highly esteemed spirit usually sold in Great Britain under the title of Jamaica Rum. He gives directions for adapting the capacity of the distillery to that of the sugar house, and especially provides that there must be at least one large cistern equal in size to the contents of four fermenting vats, to receive the lees and the dunder. He regards the lees as indispensable in the distillation of rum, and the want of them is seriously felt at the beginning of the season. He advises the following mixture as a proper one for fermented skimmings:

Skimmings 40 percent
Water 40 percent
Lees 20 percent

When molasses is procurable, he recommends one-third each of skimmings, lees and water, and 5 percent of molasses.

After the crop, however, has been harvested and there is a scarcity or total want of skimmings, the distiller must have recourse to his molasses, and the proportion of lees must be increased with regard to the increased tenacity of the sweets.

In this condition he recommends equal proportions of lees and water 40 percent, with 20 percent of molasses. The fermentation, it is stated, is not finished before the end of 10 days, but after a good supply of lees is obtainable it may be finished in five days.

The still used in these days was a very old fashioned one and the top was hated on instead of being secured by clamps or packing. Great attention must be paid to the luting of the head of the still, he says, which is done with clay, and that unless great care is used the alcohol may break out through the crevices and take fire, to the imminent danger of the persons in attendance. The overseer he advises never to leave the still, unless relieved by equally competent assistants. The first distillation in these days was called “low wines.” The strength of the spirit was proved by the bubble, or in the absence of bubble by olive oil, and the spirit was to be made of such a density that olive oil would sink to the bottom of it.

Disposition of the Rum.—A great deal of the rum made in the United States is entered for consumption. Other parts are bought by rectifiers, mixed with neutral spirits, made from corn or molasses, artificially colored, and sold as rum. A very considerable portion of the rum made in the United States, is sent to Africa, and disposed of to the semi-civilized and savage tribes of that continent. The well-known love of the natives of Africa for alcoholic drinks indicates that the markets of that country are particularly favorable to the disposal of large quantities of rum. What the effect is upon the welfare of the natives is a matter which, insofar as I know, has not been taken into consideration in the preparation and shipment of these products.

Quantity Produced, 1917.—Practically all the rum produced in 1917 was made in the Third Massachusetts District (2,706,414 gallons) and Sixth Kentucky District. The total quantity was 2,842,834.3 gallons. The quantity remaining in bond was 906,042.5 gallons.

The total quantity withdrawn from bond and tax paid was 642,798 gallons and the quantity bottled in bond 17,019.7.

The quantity of rum exported was 1,030,249.9. Of this there was sent:
To Africa 778,057.3 Gallons
To England 122,081.5 Gallons
To China 42,400.3 Gallons
To Holland 30,73<> Gallons
To Canada 24,232.6 Gallons

The dearth of ships has greatly decreased the amount of exported rum to Africa over that of previous years. In 1916, 1,196,905 gallons of rum were exported to Africa alone.

Adulteration of Rum.—As in the case of whisky and brandy rum has been subjected to all kinds of adulteration. So great had become the adulteration of rum shipped to England from Jamaica that for every barrel of rum sent 6 barrels were sold. It is not difficult to see how seriously the industries of the island of Jamaica have been crippled. Thus by the better execution of the English food law and the application thereto of the merchandise marks act, a great deal of the adulteration has been eliminated. There is still enough practiced to excite grave concern in the minds of those who make the pure product, and depend upon England for its market. There is no doubt that similar frauds are perpetrated by the rectifiers in this country.

H.W. Wiley’s Prohibition Era Telling of the Chartreuse Tale

This prohibition era telling of the Chartreuse legal situation comes from H.W. Wiley’s 1919 text, Beverages and their adulteration, origin, composition, manufacture, natural, artificial, fermented, distilled, alkaloidal and fruit juices. Wiley was a government Bureau chemist and former employer of New England rum architect Harris Eastman Sawyer. His job title gave him a privileged position, making him very much like IRS chemist Peter Valaer, but his writing style is very different and you can tell he wasn’t as brilliant.

The entire book is unique because it educates about spirits during prohibition from a privileged position (samples of everything came through Bureau labs). There is weird emoting and you can tell a subversive tone lurks throughout the whole book. When he includes different recipes for absinthe while denouncing it as evil, you wonder what his real position is. When he takes extra time to describe what are likely his favorite spirits, you wonder what his true position is on temperance was. The book is barely about adulteration, which after you spend enough time with it, seems like a ploy to get it past the censors and into the public libraries.

Anyhow, I was not aware of some of these details on the Chartreuse legal situation. Other liqueurs get no such attention besides absinthe.

Wiley’s telling of Chartreuse:

Chartreuse.—The first distillations of Chartreuse were made by St. Bruno in 1084. In 1656 after the lapse of 6 centuries the profits were so great that the monks erected a million dollar monastery at Fourvoire. The maximum annual Fourvoire production reached the huge figures of 80 million liters. Twelve different kinds of herbs were used. When gathered they were dried in well aired-cellars underneath the monastery and then macerated in water. It was this aqueous extract which mixed with alcohol and distilled gave the desired flavor to the product.

Use of the Term.—Since the expulsion of the religious orders from France and the consequent emigration of the Carthusian Monks from Grenoble, considerable confusion has arisen in different parts of the world respecting the use of the term Chartreuse. It was claimed by the French and this claim was sustained by their courts, that the administrator of the estate of the monks, appointed by the Republic to conduct the operations for the making of Chartreuse, was authorized to use the old name upon the product which he advertised. It is true this product was not made according to the secret formula of the monks, because no one knew exactly what that formula is. It was possible with the skilled labor which the administrator could secure, to produce a liqueur which resembles in many of its important respects the genuine.

The New Product.—On the other hand, the Carthusian Monks when they established themselves in Tarragona in Spain, continued the manufacture of the liqueur after the recipe which they had used at Grenoble, gathering the same kinds of herbs they had used at Grenoble from the Pyrenees, and in every other respect imitating the liqueur formerly made at Grenoble. The natural difference in the aromatics employed, and the change in the environment of manufacture resulted, as might have been expected, in the production of a liqueur which was distinctly inferior to that previously made near Grenoble. They called the new product Liqueur Peres Chartreux.

Thus the world was a double sufferer, since the French with the same materials at Grenoble could not make the Chartreuse the monks made before, and the monks with the same materials at Tarragona could only make an article inferior to their former product.

Decision of the Courts.—The question as to who had the right to use the word “Chartreuse” has been decided in the United States Courts. Judge Coxe, called attention in an interesting way to the essential points of contention:

The courts of France by a decision on March 31, 1903, dissolved the order of the Carthusian Monks at Grenoble and sequestered the entire property and appointed a receiver therefor. The court also held that all the business of the monks, including their good-will, clientage, trade marks, commercial names, models of bottles, flagons, cases, furniture, machinery, raw material, manufactured goods and the exclusive right to the industrial name L. Gamier, was the property of the monks and as such passed to the receiver to be liquidated. Thus it appears that every right and title which belonged to the monks, whether corporeal, or incorporeal, tangible or intangible, was, so far as the laws and courts of France are concerned, vested in the receiver appointed by the French Government.

The federal court also summarized the situation as to the monks and found that had they chosen to do so they could, with some necessary changes, have used the old label and trade marks in Spain; but they have seen fit not to do so probably because the labels would have been prohibited in France and they would thus have lost the French market, which, of course, is the most important. They could not have used the trade mark in the form registered in France, for it would have been a falsehood and a fraud on the public to assert that liqueur made at Tarragona, Spain, was manufactured at the convent of the Grand Chartreuse in France. This especially would have been a false statement, since the monks even had claimed that the peculiar excellence of their product came from the plants and herbs grown in the Alps in the vicinity of their Monastery.

It appears, therefore, that on their establishment in Spain, the monks of their own accord abandoned the use of their former labels and trade marks and put on their bottles an entirely different label, calling their product Liqueur Peres Chartreux.

The U. S. court also held that the use of the old labels by the French liquidator, or the parties to whom he sold the right, would prove deceptive to the customer, who would not only think that the liqueur was made as before at the Grand Chartreuse at Grenoble, but unless he Was familiar with the processes of the courts in France, would think also it was made by the monks themselves. Hence, any label used by the liquidator, or any one authorized by him, which would convey such an idea; that is, any label which was exactly similar to the old label used by the monks, must, of necessity, be deceptive. Thus any liqueur made subsequent to 1903, cannot be legally called Chartreuse in the United States.

Selected Writings of Fermentation Chemist S.F. Ashby

This is a very cool and very long selection of works by fermentation chemist S.F. Ashby who came after Charles Allan and Percival Greg. It is not for everyone and probably just for distillers and rum makers interested in getting deeper into fermentation. These works are still cited 100 years later by some of the foremost rum researchers. What I’ve done is made the document more accessible and better indexed so more people will find it in searches.

If you are just a casual rum enthusiast it may still be fun to read or skim. You can see how much they knew and didn’t know about fermentation in the glory days of Jamaican rum. You can also see their methodology for getting a handle on it all and deepening their involvement. Sadly, so much of the rum made these days by the new distillers aren’t that sophisticated. They are still in the “look mom I’m making rum” phase and not exactly sculpting their product yet. As I’ve said before rum is the most malleable of all spirits, but you can’t start to shape it without doing serious homework and pretty involved experiments.

One more notable thing is that towards the very end there is an awesome account of making Jamaican orange wine and orange wine vinegar.

Somewhere in there is also the first mention I’ve ever come across of Marshal Ward’s ginger beer plant which is a type of SCOBY used to ferment the original Jamaican ginger beer.

I spent three weeks in Jamaica a few years ago and hated it. My boss had sent me to supervise a house that was under construction. There was so much that could be done there but no one was doing anything. I scoured the island looking for moonshine and found nothing. So much of the jerk chicken I was coming across was made with Chinese barbecue sauce. I have a dream of returning some day to start a Noma style restaurant with a large beverage focus and revive so many of the great products that used to be there until they consolidated into virtually nothing which was then undermined by cheaper Chinese imports. Give me a few years, I still have a lot more to learn.


It had been established during the three years that my predecessor Mr. Chas. Allan, B. Sc. had worked on the manufacture of Jamaica Rum, that flavour was mainly due to the compound ethers. These bodies were considered as produced by chemical combination of alcohol with various volatile fatty acids during and after fermentation of the wash, and particularly during distillation. The alcohol was the product of the action of yeasts on the sugar in the wash, but the acids were the work of bacteria, being partly preformed in the materials used for setting up the wash, and partly produced in the wash during and after the yeast fermentation. The following acids were found, acetic, propionic, butyric, capryllic, capric, lauric, all of which yielded ethers with alcohol capable of giving varied flavours to Rum. Acetic ether was shown to constitute about 98 per cent, of all ethers in Rum, but contributed little flavour and owing to its volatility was very transient. Butyric ether was found to be more valuable, but the ethers of the higher acids, capryllic, capric, and lauric, were held to be of special importance for giving both body and characteristic flavour.

As the yeasts were considered to be only alcohol producers attention was mainly directed to the study of bacteria producing the valuable acids. One such bacterium was isolated and the conditions under which it works determined (Report 1906, pages 136-137). A microscopical examination of washes showed the presence of two yeast types, distinguished by very different modes of multiplying; to the one type belonged, the oval and sausage shaped forms which multiplied by budding (Saccharomycetes) whereas the other type reproduced by division through the middle of the cell, that is by ‘fission.’ (Schizosaccharomycetes). The oval budding forms were alone seen in cane juice washes, but the fission type was found to be the characteristic fermenting yeast of both common, clean and flavoured rum washes. The latter kind could not be isolated, and indeed no systematic experiments appear to have been made with any of the yeasts.

Mr. Percival H. Greig of Westmoreland was the first to isolate a number of Jamaica Distillery yeasts, and to study their action on washes in a state of pure culture. In molasses and dunder which he took to Jorgensen’s Laboratory in Copenhagen in 1893 the fission type of yeast was discovered and studied for the first time. Greig continued to work with these yeasts in Jamaica till 1896 and published reports of his results in the Bulletin of the Botanical Department (March, August, and September 1895 and January 1896). He observed marked differences in the time required for fermentation, amount of attenuation, and alcohol-yield with different yeast, and drew particular attention to a slow working top fermenting fission form which alone was able to produce an agreeable flavour in washes. He recognised the importance for flavouring of fruit ether in rum, but appeared to think that these bodies in so far as they were not contained in the original juice of the cane, could be produced at will by pitching the wash with a suitable flavour engendering yeast. On these grounds he strongly advocated the employment of pure yeast cultures in Jamaican Distilleries, and insisted that the distiller should strive to suppress the action of bacteria.

As previously indicated Mr. Allan took up the precisely opposite view, pushing the yeasts into a subordinate position and devoted his attention mainly to the search after flavour producing bacteria.

As the yeasts must always be the central factors in fermentations for the production of spirits, it appeared to me natural to devote first attention to them, and to observe in particular whether some are really able to engender flavours of value in Jamaica Rum.


Early in the year I isolated and obtained in pure culture a number of the oval budding yeasts from washes in the Laboratory distillery which were set up from a mixture of fresh cane juice and dunder, and about the same time some fission yeasts were secured from a dead wash sent in from the country. As the result of some preliminary fermentation experiments it was observed that the oval cane juice yeasts worked more rapidly in washes of low acidity, but with an acidity of nearly I per cent, the oval yeasts showed very sluggish fermentation, while the fission type worked as well at the high acidity as at the low.

It seemed desirable to study the effect of three common distillery acids, lactic, acetic, and butyric, on the two types of yeast, and accordingly a number of fermentations were set going in cane juice and dunder washes to which varying quantities of the single acids were added before putting in the yeast. The oval budding yeasts all showed bottom fermentation phenomena, but the fission yeasts all showed strong top fermentation with the production of an abundant fatty head. A vigorous yeast of each kind was selected for the experiment with the acids.

The amounts of the different pure acids added are expressed also as Sulphuric acid by weight per cent, of the wash by volume. The amount of the yeast added was as far as possible the same for both types, except in the butyric acid series, which was carried out at a later date with a larger amount of yeast. The results are set out in Table I. which shows the amounts of sugar fermented at the end of each day to the sixth day. The figures were obtained by daily weighings, multiplying the loss of weight by two and calculating the resulting numbers 011 the total amount of sugar originally present.

With regard to acetic acid the results show that the budding yeast is much more susceptible to it than the fission yeast. In the presence of a half per cent, of this acid the budding yeast showed greatly reduced fermentation during the first three days, whereas the fission yeast was but slightly affected. One per cent, completely prevented the activity of the budding type, but again only slightly reduced the fission yeast fermentation. Both yeasts are very resistant against lactic acid, but even here .7 per cent, showed an injurious influence on the budding yeast, whereas, 1.4 per cent, hardly reduced fermentation by the fission yeast. Butyric acid proved to be very poisonous for both yeasts, but whereas .15 per cent, wholly prevented the budding yeast from fermenting it caused the period of fermentation to be increased by only one day with the fission type. Even .4 per cant, did not completely suppress the latter’s activity, but .5 per cent, prevented all fermentation.

The conclusion to be drawn from these results is that the budding yeasts are suitable only for the fermentation of weakly acid washes, whereas the fission type is at home in washes of high acidity. A notable point which the figures bring out is that where the acidity is low the budding yeasts get to work greatly more rapidly than the fission yeast. This is particularly well shown in the case where no acid was added. Although both yeasts completed the fermentation in five days, the budding yeast multiplied and fermented much stronger in the two first days. The ability of the budding type to multiply and ferment more rapidly from the outset in the weeker acid liquors, like cane juice washes and fresh skimmings, explains why this is the only kind found in such liquors the acidity of which is generally under .5 per cent. In the usual estate washes containing dunder, molasses, acid skimmings, and frequently specially added acid, the budding yeast is largely suppressed, but the more slowly developing and very acid resistent fission type takes possession, and is practically the only form found in washes the acidity of which is 1.0 percent, and over.


In March I collected samples of fermenting washes, dead washes, skimmings, dunder, acid and rum, from several estates in Westmoreland and St. James, and from the washes was able to gain pure culture of many fission yeasts. These cultures were started from a single cell according to the method of Hansen in order to prevent the possibility of any of the growths consisting of mixtures. With ten of these derived from four estates a fermentation series was set going in a wash of the composition :—

The Brix was 17.4, the Acidity .48 per cent, and the total sugar present 14.5 per cent.
The yeasts 3 and 9 although pure fission forms, showed a totally different kind of fermentation to most of the others, the yeast gathering mostly into a coherent mass at the bottom of the vessels, the bubbles breaking on the surface being glassy clear and containing practically no cells. This fermentation was evidently strictly of the bottom kind. Yeast 5 showed mainly bottom fermentation phenomena, but produced also a slight yeasty head. All the other yeasts formed a strong glistening brownish white head at the surface and the bubbles were thickly cloudy, these yeasts were accordingly strongly top fermenting. Under the microscope the two forms could be distinguished easily, the bottom type showing isolated and paired cells, but never more than two together, whereas the top yeasts showed long chains of four or more cells interlaced and apparently branched. Yeast 5 showed no chains but the cells were often united mechanically into flocks.

The bottom yeasts 3 and 9 completed the fermentation in two days less than the top forms, yeast 5 occupying an intermediate position. This character of the bottom yeast to ferment more vigorously than the top kind has preserved itself in all subsequent experiments. The increase of acidity due to the yeast alone, all bacteria having been excluded, amounts to only about .1 per cent. The attenuation was very much the same in all cases, but the highest amounts of proof spirit were obtained from the bottom yeast 9 and the mainly bottom yeast 5. The yield of proof spirit per degree attenuation was good, in four cases exceeding unity. The distillation was effected from glass apparatus with one retort, the liquor being divided into two parts, the first yielding high wines of 20 O.P. and the second portion giving rum of 41 O.P. with the high wines in the retort. The rum could hardly be called by that name, and it showed the same character for all ten yeasts; in no case was any characteristic flavour produced.

In another experiment with dunder, molasses, and water, a much larger amount of dunder was used, namely one half the bulk of the wash.

The Brix of the mixture was 18.6, Acidity .7 %.

The Bottom yeast here showed a gain of 2 to 3 days in the fermentation period. The yield of proof spirit was very high. The rum obtained was very light, and gave no difference in flavour with the different yeasts.

In another fermentation series with the yeasts 2 and 9 pure volatile acids were added to the molasses and dunder wash before pitching with the yeast. The Brix was l8.6, the natural acidity of the wash .46. Acetic acid was added equal to .5 acidity, and butyric acid equal to .1 acidity, so that the total acidity before fermentation amounted to 1.06.

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The large amount of volatile acid added had a marked effect in slowing fermentation, the time required as compared with the previous experiments, being 10 days as against 6 days with the bottom form,and 16 days as against 9 with top yeast. The rum showed an improvement in flavour, and with the top yeast contained more than twice as much ether. This was due to the much longer period during which alcohol and volatile acids could react chemically to produce ethers in the wash containing the top yeast.

The conclusion to be drawn from these experiments is that, whereas, none of the fission yeast isolated from the estate washes was able to produce flavour on its own account, the top yeast owing to its slower fermentation admitted a greater amount of chemical ether production in a wash originally high in volatile acids. The latter result is in accordance with distillers’ experience as they consider that a wash showing a strong fatty head due to the top fermenting fission yeast yields the best flavoured rum.


It is well known that the alcohol accumulating during fermentation has, beyond a certain concentration, different with different yeasts, a marked slowing effect on fermentation and finally stops it all together. In order to test the maximum amount of alcohol endured by the Jamaica fission yeasts, it was necessary to set up a wash of very high gravity. In a first experiment with the yeasts 2 and 9, a wash consisting of 4,000 dunder, 1,600 molasses, and 703 water was set up at 30′ Brix. This was practically completely fermented, so that the alcohol formed was below the maximum which the yeasts could endure. In a second series a wash of 30° Brix was set up with molasses and an extract of yeast, and after some days a further quantity of molasses was added. In this case both yeasts stopped fermenting due to the action of the alcohol, while there was still abundant sugar left in the wash. The data and results of the Experiments are given in Table IV.

The first Experiments show a complete fermentation by both yeasts, the bottom form taking 5 days less than the top yeast. The bottom yeast also shows a higher yield of proof spirit. The influence of the accumulating alcohol on fermentation is very marked, for whereas the bottom yeast had produced 16.5 per cent, proof spirit in 7 days, only 7 per cent, more spirit was produced in the following II days.

In the second Experiment the maximum yield of alcohol which prevented all further fermentation was just under 25 per cent, with the bottom yeast and just over 23 per cent, with the top form ; while the bottom yeast yielded 17 per cent, proof spirit in 7 days only 7.7 per cent, more was produced in the following 12 days. A similar effect of the alcohol is shown by the top yeast. The top yeast showed a rather sudden falling off in fermentation with about 18.5 per cent, proof spirit present, but the top yeast gave a more gradual falling off; it appeared, however, to be susceptible at about 16.5 per cent, proof spirit. The mixture of the two yeasts showed throughout intermediate results.

It is evident from these results that the fission yeasts which work the estate washes are capable of yielding very large amounts of alcohol in pure culture with abundant time at their disposal. Fermentation is rapid and uniform for 7-9 days, during which 16-18 per cent, of proof spirit is yielded. This means that a wash containing about 16 per cent. of sugar can be fermented in a reasonable time. Above this amount the loss often becomes serious owing to sluggish fermentation. This fact has been recognised in practical distillery work, so that estate washes are rarely set up with more than 16 per cent, of sugar and usually with less.


This Experiment was devised with a view to observing the effect of varying the amount of sugar in the wash, on time, attenuation and yield of proof spirit. The washes all contained the same proportion of dunder, namely, three-fifths, the gravity being varied by means of the molasses. The results were as follows:

Here as usual the bottom yeast is the most rapid worker, showing 1 gain of three days. The time required is least with the lowest gravity, but there, is a difference of two days between the 25 and 20 settings and of only one day between the 20 and 15 settings. This difference hardly shows itself during the period of the main fermentation. After five days the relative amounts of sugar fermented by the bottom yeast were 35, 51, and 68.

As there was a half more sugar in the 20 setting as in the 15, and twice as much in the 25 setting, these figures indicate that the activity of fermentation was proportional to the amount of sugar present, i.e., in a given time twice as much sugar was fermented in the 25 setting as in the 15 setting, the 20 setting coming half way between. The difference, however, was shown by the time taken by the wash to die off after the main fermentation was over. The 25 setting took 3 days to die, the 28 setting I day, and the 15 setting only a few hours. The yield of proof spirit was as high for the highest gravity as for the lowest, and the bottom yeast gave as usual the best results.

On the other hand there was markedly more sugar left unfermented in the highest setting than in the other two, and the bottom yeast in all three case left more than the top yeast. The dunder employed in this series was a light cane juice product having a Brix of 9 and an acidity of only 1.2. The amount which had to be used (3/5 of the wash) to secure a normal acidity was more than is usual in practical operations, where the dunder has an acidity of over 2 per cent. The result was that the relative amount of sugar in the wash was low, and the attenuation and yield of proof spirit low also.


The yeast produced in some of the fermentations of the last experiment was collected, dried in the air and weighed. The results are shown in pounds for 1,000 gallons of wash.

The top yeast produces a half more yeast substance than the bottom yeast consequently a pound of the bottom yeast is able to ferment a much greater amount of sugar. The amount of yeast produced by the top variety falls away with the reduction in gravity of the wash, so that only one half as much yeast is produced in a 15 Brix setting as in one at 25 Brix. The amount of yeast produced is proportional to the amount of fermentable sugar present for washes from 25 to 15 Brix, but at 30 Brix relatively less yeast is produced, so that the ratio to sugar fermented is wider.

At first sight it seems inconsistent that the top yeast should often attenuate more than the bottom yeast and leave less sugar unfermented, yet give a lower yield of proof spirit. The above results, show however, that it removes no more sugar to build up its substance than the bottom yeast, and owing to its habit of gathering at the surface of the wash in intimate contact with the air, respiration is more active, causing a greater loss of sugar by combustion into water and carbonic acid The bottom yeast is consequently a more economical worker.

Stability of the two Varieties

Distillers often observe that during the advance of the season their fermentations which were at first of the bottom type, tend more and more to top characters, suggesting either a conversion of the bottom yeast into the top or else a gradual displacement of the former by the latter due to some change in the composition of the wash which favours the top yeasts. That top and bottom fermentation may proceed in the same wash, was evident from the fact that both forms were in several cases isolated from the same material.

Some observations have made it seem probable to me that at any rate one of the varieties is not stable. The fission yeast No. 3 when freshly isolated showed wholly bottom-fermentation phenomena, and agreed entirely with the other bottom yeasts. It was allowed to lie for two months under a fermented cane juice wash, and was then freshened up again. I was surprised to find that it no longer showed bottom fermentation, but gave a strongly marked top fermentation. On comparing its behavior with that of yeasts which had always been top fermentation, it was found that it gave quite similar results, i.e., an equally slow fermentation and a lower yield of alcohol than the bottom yeasts. Under the microscope it also was identical with the top form. The view which remained for many years unchallenged in Europe was, that the top and bottom yeasts were distinct types, the one never passing into the other. Quite recently Hansen has shown however, that there is always a tendency to vary, and has actually obtained the one form from the other in the case of a number of brewery and wine budding yeasts. There appears to be a much greater tendency for bottom yeasts to go over into the top form than vice versa. Further observations must show whether the fission yeasts are particularly liable to vary in this way, and whether the change so often seen in distilleries in Jamaica from bottom to top fermentation is due to a variation of the yeast.

Conclusions with regard to the two varieties of Fission Yeast.

I—The bottom yeast is a characteristically more rapid worker than the top yeast giving a gain of 2 to 3 days in the fermentation period.
2—The bottom yeast forms less substance and consequently makes a smaller claim on the amount of food stuff in the wash.
3—The bottom yeast gives a rapid and uniform fermentation during the main period, but the wash dies slowly. The top yeast ferments very uniformly throughout, and shows no sharp transition to the final stage.
4—The yeasts attenuate about equally, but the bottom yeast gives a better yield of alcohol.
5—The top yeast leaves less unfermented sugar in the wash.
6—The bottom yeast gives a higher maximum yield of alcohol, namely 25 per cent., as against 23 per cent., with* the top variety.
7—The bottom yeast shows the injurious effect of alcohol at a higher concentration than the top yeast, viz., II and 16 respectively.
8—Owing to its slower fermentation the top yeast admits of more ethers being produced in the wash than the bottom yeast where volatile acids are present. The rum is consequently better.


Owing to insufficient distillery space or small still capacity, it often happens that molasses have to be stored for weeks during which period they undergo a rather active fermentation. This involves a loss of sugar, so that it seemed desirable to make some experiments with a view to (1) determining the amount of loss arising from the cause. (2) separating and studying the properties of the yeast causing the trouble. (3) finding a remedy for it.

Three yeasts were secured in pure culture from a fermenting molasses, all of which were able to set up fermentation in a liquor of very high gravity.

YEAST (a)—This was a budding form of the pastorianus type which formed spores on the gypsum block at the air temperature in under 18 hours. Transfered to mixtures of molasses and water of increasing gravity it fermented actively at 45Brix, feebly at 60 Brix, and showed no fermentation in molasses alone of 90 Brix. It was therefore not the kind active in the stored material.

YEAST (b)—This was a fruit ether producing yeast forming a dry wrinkled friable skin on ordinary washes. It was a small budding yeast which formed hat shaped spores on the gypsum block in 24 hours. It fermented strongly in molasses and water of 45 Brix, more weakly at 60 Brix and not at all in molasses alone. It was also therefore not the form desired.

YEAST (c)— This was a small spherical or oval budding form characterised by the production of branched chains of cells in weakly acid washes, and a very abundant multiplication. It formed no spores and no skin on cane juice, but merely a yeast ring. It appeared therefore to be no true yeast, but a ‘torula.’ This kind fermented actively in molasses and water of 45 and 60 Brix, and also in pure molasses of 90 Brix. It corresponded to the form most abundantly present in the original material, and was evidently the true agent.

As an alkaline medium acts very unfavourably on yeast fermentation lime suggested itself as the first substance to try as a remedy. In one experiment the molasses were allowed to ferment spontaneously without the addition of lime, and with the additions of 6, 12, and 18 lbs. of dry lime to every 100 gallons of molasses, the lime being added as fresh milk of lime and well stirred in. The same experiment was repeated with sterile molasses into which a pure culture of yeast (c) had been introduced, but here only 3 and 6 lbs. of lime were used. The fresh molasses had a Brix of 90 and contained nearly 70 per cent, of sugars. After six weeks the Brix was determined and found to be as follows :—

The molasses alone fermented strongly with crude and pure yeasts from the outset. With 6 lbs. of lime there was no fermentation for nearly three weeks, when it started, but was much stronger in the pure yeast culture. 3 lbs. of lime in the pure yeast culture did not prevent fermentation from starting within a few days. With 12 lbs. of lime in the crude culture fermentation had only just started between the 5th and 6th week. With 18 lbs. of lime there was no growth of yeast and no fermentation. In the crude there was a maximum loss equal to 15 per cent, of the total sugar, and in the pure culture this loss exceeded 21 per cent. Lime in small amount was therefore capable of checking this fermentation for a time, 6 lbs. to 100 gallons being sufficient to preserve the molasses for nearly three weeks. As the lime gradually losses its alkalimity and goes into the neutral carbonate the fermentation starts afresh. As it is very undesirable to bring an alkaline molasses into a distillery wash as small an amount as possible should be used to check the foaming 6 lbs. of lime to 100 gallons molasses should be used at first, the lime being freshly stirred up into a milk with a few gallons of water, but only enough of the latter to admit of a thorough stirring into the molasses. If after a time foaming shows evidence of beginning again a further smaller amount of lime milk must be stirred in.

The yeast or ‘torula’ (c) ferments very sluggishly in a dilute molasses wash, and hardly at all in cane juice. Judging from the Experiments with the molasses, it is able to produce about 14 per cent, of proof spirit. It cannot invert cane sugar, and hence the feeble fermentation in cane juice, but only attacks the ready formed invert sugar in molasses.


As this yeast in pure culture gave a very marked flavour to washes in which it was fermenting some preliminary experiments were made with it in different media, the Rum distilled off and the Ethers determined therein. It was grown in three washes ;—

(i) Molasses and water Brix 15 Acidity .10
(2) Molasses, half dunder and water Brix 15 Acidity .34
(3) Tempered cane juice and one sixth dunder Brix 15 Acidity 20.

The yeast formed the dry wrinkled surface skin in a couple of days in all the washes, and multiplied abundantly, at the same time the fruity odour was very perceptible. Fermentation was very slow, the time required for the washes to die was;—

In spite of the very high ether content the rum had a pleasant fruity flavour with no trace of ‘pepperiness.’ These result were obtained by a simple distillation without any treatment of lees. The ethers consisted mainly of acetic ether, so that the yeast is able to produce both alcohol and acetic acid. There was no increase of ether production during distillation as a portion of (1) was neutralised before distilling and gave the same amount of ether as the un-neutralised part, namely 18.000.

The increase of acidity during fermentation was inconsiderable, a result which taken from the preceeding one makes it highly probable that ether formation does not occur by a merely chemical reaction in the wash, but takes place in intimate relation with the actively working yeast cell.

Further work is being done on this yeast with a view to its introduction into distillery practice.


Two perfectly different species of Acetic Acid Bacteria were isolated from acid skimmings and dead washes.

I. A form which appears quickly on dead washes both of low and high acidity. At first a delicate blue dry friable film which becomes white when strongly developed, but is always easily broken up. In a glass vessel the film climbs up the sides high above the surface of the liquid. It consists of short rather plump rods which stain yellow or yellowish brown with iodine, but never blue, and forms only short chains. It resembles Bacterium Kutzeanum of Hansen except in its inability to turn blue with iodine.

II. A Bacterium which forms a very tenacious cartilaginous skin in skimmings and dead washes, consisting of long narrow rods. The skin turns blue with iodine and sulphuric acid, and is in all respects similar to Bacterium Xylinum of A. Brown.

In order to observe the highest concentration of alcohol which admits of a development of acetic bacteria a dead wash holding 23 per cent, of proof spirit was exposed to the air. For six weeks there was no sign of an acetic film, and there was no rise in the acidity. Between the sixth and seventh week a film began to form and at this stage the liquor contained 14 per cent, proof spirit, 9 per cent, having evaporated away from the wash.

In another experiment a dead wash containing 24.7 per cent, of proof spirit was diluted with water in varying amounts and seeded with a pure culture of acetic bacterium I. The progress of acidification is shown in the following table, the figures representing the increase of acidity expressed as Sulphuric acid per cent.


More alcohol was added to c, d, and e, after three weeks, and the acid rose to 6.2, 5.8, and 5.3, respectively in another week, but showed no further increase. The greatest amount 01 acid produced was therefore equal to about 7.5 per cent, of pure acetic acid, the largest quantity which the bacterium could endure. The organism could not grow and work in 24.7 per cent of proof spirit, and showed only feeble activity in 16.5 per cent, but in 12.3 per cent, it worked strongly. The evidence shows therefore the amount of alcohol which can undergo vigorous acidification is between 12 and 16 per cent proof spirit, which agrees with the result of the first observation.

The theoretical maximum amount of acetic acid which could be formed from the alcohol in cultures c, d, and e, is 7.3, 5.9, and 4.9 per cent. The actual amounts formed in 20 days were 5.7, 5.2, and 4.6 so that
in c 78 per cent of the possible was formed,
”  d 89
”  e 94

The lower the amount of alcohol in a liquor, the more completely therefore is it oxidised to acetic acid. For practical purposes the highest acidity was reached in a fortnight at about 4 per cent. Bacterium II. proved to be unable to grow and produce acid in a dead wash containing 12 per cent proof spirit, but gave over three per cent acid in a liquor with 8 per cent proof spirit. This bacterium also makes greater claims upon the nitrogenous foodstuff in the liquor than bacterium I. Bacterium I. is therefore the characteristic acetic acid producer in all liquors containing 10 per cent and more of proof spirit, such as ordinary dead washes, while bacterium II. works best in liquors like fermented skimmings and fermented rum cane juice.

The following table shows the amounts of Total and Volatile acid (mostly acetic acid) and the relative amounts of volatile acid to total acid in some distillery liquors. Of special interest are the quantities of volatile acid in such materials as acid skimmings, and flavour, because in these liquors an attempt is made to produce as much volatile acid as possible. The volatile acid shows an average percentage of the total acid of from 22 to 27, or only about one quarter of the acid present is volatile. As the fresh skimmings which comes down from the boiling house are practically neutral the great part of the acid produced in the cisterns is the work of bacteria. Although the skimmings readily undergo fermentation, this is not entirely due to yeast, as the liquor is heavily contaminated by bacteria which produce fixed acids such as lactic from sugar. A number of such bacteria have been separated from the skimmings. They include the well known rice grain bacterium, which can nearly always be found in skimmings. It forms large rounded gelatinous masses when strongly developed consisting of enormous numbers of hand shaped colonies, the rod shaped bacteria being embedded at the ends of finger like processes of the jelly. This bacterium produces lactic acid and forms its jelly at the expense of the sugar present. Another rod shaped organism often develops in fresh cane juice contaminated by dirt from the mill or by soil, at a great rate, and converts the liquor in one day into a thick viscous mass in which yeast can only work very sluggishly. Gas and lactic acid are produced, the viscous substance being formed at the expense of the sugar. The presence of such objectionable organisms account for the poor yield of alcohol in skimmings, and the small amounts of volatile acid. Acetic acid bacteria are wholly dependant upon oxygen for their work of converting alcohol to acetic acid, and require therefore that the liquor in which they are working should expose as great a surface as possible to the air. This is only being imperfectly attained in distilleries even in the trash cisterns. It is proposed therefore to Experiment on a practical scale with a view to the more rapid and more abundant production of acetic acid from alcoholic liquors.


By S. F. ASHBY, B.Sc, Fermentation Chemist.

1. Useful Information’ Regarding Estate Distillery Materials.

Skimmings or Scummings—A mixture of liquor and solid matters skimmed from the surface of juice in clarifiers and coppers (if used) together with wash water from coppers, etc. The solid matter a mixture of pulverised cane fibre (trash), phosphate of lime, pectic and waxy matters, and coagulated albumen. According to the amount of solid matter and of dilution the gravity may vary when quite fresh from that of the juice (15-20 Brix) to under 10 Brix. The reaction to litmus is either neutral, faintly acid or faint alkaline.
Dunder—The liquor left in the still after distillation is completed. A yeast extract. The gravity varies according to materials fermented from under 10 Brix to over 25 Brix, and the same applies to the acidity which varies from about 1 per cent, to over 3 per cent. It is never free from sugar which varies from 0.2 per cent, to over 1 per cent. Sugars other than hexoses (pentoses) and allied bodies may be present which reduce Fehling’s solution but are not fermentable by yeast. On an average about 1 percent, of glycerine has been found in Dunder. It is never free from volatile acid.
Its high density is due to cane and yeast gum and caramel (especially if still is direct fired.)
Molasses—The sweet viscous syrup separated from the crystalized sugar by the centrifugals. It is markedly acid (about 0.5 per cent.) has a specific gravity of about 1.45, contains about 40 to (50 per cent, cane sugar, and 10 to over 20 per cent, glucose. One gallon (imperial) contains 8-10 pounds of fermentable sugar.
Acid—Skimmings, normal cane juice, or rum cane juice, allowed to sour. The production of acetic acid is the object sought. The volatile acidity rarely exceeds 40 per cent, of the total and is usually under one third the total.
The souring is carried out either with trash cisterns or without the addition of trash. The liquor ferments (yeast) and sours simultaneously.
Lees—The liquor left in the retorts after distillation is completed. It contains a high proportion of volatile acid.
Wash—The liquor (prepared from the mixed materials) which is actually fermented and distilled for rum. The mixing of the materials is called “setting up.” When fermenting it is “live” wash, and when fermentation has ceased it is “dead” wash.
Flavour and “Muck Hole”—(See description in first Sugar Experiment Report.)
Rum—The early portion of the alcoholic distillate; (the preliminary runnings if cloudy are rejected) its strength varies from 36 to over 40 proof as determined by the “bead.” It is water clear (white Rum). Before leaving the estate “Rum store” it is coloured by caramel boiled by the distiller. Each estate has its own standard of colour.
High Wines—The running from the still which follows the rum; collected to a strength of about 20 over proof.
Low Wines—The subsequent runnings collected till all alcohol has distilled over. The strength varies from 40 to 60 under proof.
Retorts—Copper vessels inserted between the still and the coil. The vapours from the still must pass through them. Most estates have one retort which contains the high wines of a preceding distillation. Some estates have both ”high wines” and “low wines” retorts, the latter next to the still. The retorts have a capacity of about 1-10 that of the still.
Low Wines Rum—Some estates with one retort (high wines) add the low wines to the wash in the still; other estates, however, distill the low wines independently (they run about one low wines still to 5 or 6 ordinary wash stills) and obtain “low wines rum” a product of inferior quality and price.

Types Of Rum.

The two main kinds of Rum are “Common Clean” and “Flavoured or German.” The individual estates confine themselves to the manufacture of one of these kinds. Nearly all the “Flavoured” Rum is made in the parish of Trelawny.

Common Clean Rum—may be divided into two kinds depending on the materials used.
1. From washes set up with a mixture of skimmings, dunder, molasses and water. The materials are not allowed to sour. Several estates with up-to-date boiling house plant (vaccuum pans, etc.) and a consequent large out put of skimmings and molasses employ this method. The materials must be used rapidly, and fermentation rendered of as short duration as possible. The wash is set up with 1/3 skimmings, 1/3 dunder, and molasses and water to give an initial gravity of about 10 Brix. The wash attenuates in about 4 days to 3 or 4 Brix. The initial sugar content is about 11-13 per cent, and the attenuation from 11-13 degrees. The rum is light in body and of low ether content, and is mainly consumed locally.
One or two estates which do not make sugar boil their juice and ferment it with dunder. (Appleton).
2. From washes set up from the same materials and also with “acid” prepared either from skimmings, rum cane juice or normal cane juice. The composition of the wash varies:—

The gravity of the setting depends largely on that of the dunder which varies from 10 to 20 Brix. As a rule the setting is not lower than 18 Brix. and may be as high as 24 Brix. The initial sugar content varies from 10 to 14 per cent, and the attenuation corresponds to that. The fermentation period depends on both the acidity of the dunder and on the quantity and acidity (especially the volatile) of the “acid.” The wash ferments from 5 to 9 days and is often allowed to lie for a couple of days when dead.

The only acid produced is evidently “acetic” and some of these rums may contain over 1,000 ethers (Swanswick, Long Pond) where much “acid” is used in the wash.

The yield of proof spirit is from 0.85 to 1.0 per cent, on the sugar fermented and on the attenuation 0.8 to 0.9 per degree. From 5 to 10 per cent, is lost in distillation.

The yield of rum 40 o.p. varies from 60 to 90 gallons per 1,000 gallons wash in still.

The fermenting cisterns (sunk in floor of distillery built of wood and backed by puddled clay) and vats are usually of 1,200 gallons capacity and the still will receive the contents of one cistern. Two stills are usually run per day (daylight). The stills are heated by steam coil or by direct fire. The rums made with ‘common clean’ materials vary in ether content from under 100 parts to over 1,000. Acetic ether is practically the only one present, and its amount depends entirely on the quantity of acid used in the washes and on the length of time the wash ferments and lies when “dead.”

Flavoured or German Rum.—These rums are made on estates having old fashioned boiling house plant where the manufacture of sugar is of secondary importance. The usual common clean materials are employed and in addition “flavoured.”

“Acid” is prepared from cane juice or skimmings in the usual way in a succession of trash cisterns. A “muck hole” outside the distillery is the receptacle for the thick matter deposited from the dunder, and the wash (dead wash bottom) to which is added cane trash and lees. The matter consists to a large extent of dead yeast and is therefore highly nitrogenous. It undergoes slow fermentation and putrefaction and its acidity is kept low by the addition of marl. When ripe it contains large amounts of butyric and higher fatty acids, both free and combined with lime. It is added to a series of acid cisterns outside the distillery where the butyric and other acids are set free. This complex acid material is the “flavour.” The flavour enters the wash after fermentation has begun owing to the presence of acids in it which are injurious to yeast, the fermentation is prolonged and the sugar is never very completely fermented out. Fermentation lasts 9 to 10 days and the dead wash lies for several days longer. An example of the kind of wash follows:—

This means a yield of 48 galls, rum per 1,000 galls, wash whereas the attenuation would indicate a yield of about 78 gallons. Only a portion of the high strength distillate is therefore collected as rum of first quality.

These rums show an ether content as a rule from 1,000 to 2,000. While over 95 per cent, of the total ethers is “acetic” there is always present several per cent, of butyric ether and still smaller amounts of esters of higher fatty acids (capryllic, caproic and lauric). Most of these rums find their way to Germany for blending and particularly for “stretching” potato or molasses spirits.


Yeasts.—Practically three yeasts perform all the conversion of sugar into alcohol in the Jamaica Distillery.
1. Bottom fermenting oval budding yeast.
2. Top fermenting chained fission yeast.
3. Bottom fermenting unchained fission yeast.

Oral budding yeast.—A typical bottom fermenting yeast the cells of which do not form chains. It is oval in shape and often rather pointed at one end. The average dimensions are 7.5-9 m long by 6-7 m. broad. It does not form a film on dead wash but at most a yeast ring. It forms spores on the gypsum block (as a rule four in a cell) in 24 hours at air temperature. It readily inverts and ferments cane sugar. This yeast is present on the rind of the cane and is always found in freshly milled juice. Spontaneous fermentation of juice is therefore always brought about by this yeast. In fresh juice it multiplies quickly and sets up a rapid fermentation. It displaces all other native yeasts in a favourable liquor like juice. The optimum temperature for its multiplication lies above 30 C. but it appears to ferment best at that initial temperature. It will work practically all the sugars out of an undiluted juice if not interfered with by acid-producing bacteria. The fermented liquor has an agreeable odour. In the experimental work at the Sugar Station Distillery where either cane juice or cane juice, molasses, and dunder are usually worked with, this yeast alone sets up and carries through normal fermentation.

On estates where the first type of common clean rum is made (i.e. without “acid “) this yeast possesses the wash owing to its properties of quick multiplication and rapid and intense fermentation. Such washes heat up quickly and temperatures as high as 108 F. have been observed. These high temperatures mean injury to the yeast, imperfect attenuation, and marked loss of alcohol by evaporation. Like most bottom fermenting kinds this yeast is markedly susceptible to unfavourable conditions such as poor food supply, excessive temperature and especially high acidity. Volatile acidity injuries it very readily (see experiments in second S.E.S. Report.)

It is injuriously affected by the fixed acids of dunder and works best where the initial acidity of the wash does not exceed 0.3 per cent. In washes with an initial acidity of 1 per cent and more it gradually gives place to more acid-resistent yeasts. On estates using acid the wash contains both this and fission yeasts, the relative proportion depending on the amount of acid employed. In common clean washes with an acidity exceeding 1.5 per cent, and a volatile acidity of 0.5 per cent, the writer found it entirely displaced by fission yeasts even quite early in the season.

Top Fermentiny Fission Yeast.—A typical top fermenting chained yeast. On washes of high acidity which are not working very intensely this yeast throws up a characteristic light or dark golden yellow thick moist creamy or fatty head which may completely cover the surface of the liquor. The bubbles of gas escaping through the head are cloudy. The head consists mainly of short, rectangular cells in chains of four or more, often in clumps and showing a kind of false branching. When shaken up in a wash the yeast forms into loose flocks which rapidly deposit. There is considerable variation in the size and shape of the cells: the size varies from 6-12 m by 4.5 to 5.5 m. and the chain cells are usually small viz., 6-7 m. long by 4.5 m. broad.

Spores are freely formed in the wash during fermentation. There are four oval spores in a cell and their walls stain blue with iodine (in iodide). The spores are very frequently found in bridge shaped sporangia formed by the reunion after division of two cells or by the union of two neighbouring cells. This yeast has a high optimum for multiplication and fermentation between 34 to 37 C. It endures high acidity (over 3 per cent. total) and is greatly more resistent to volatile acid than the budding yeast. At ordinary temperatures 24 to 27 C. the fermentation is slow but the sugar is efficiently worked out. In pure cultures the attenuation and the yield are as good as from the oval yeast.

In all washes of high total acidity (over 1 per cent.) and especially of high volatile acidity this yeast is generally present and often carries out the entire fermentation. It is the typical yeast of the “Flavoured Rum” washes.

Bottom Fermenting Fission Yeast.—This yeast produces no head in washes, the escaping bubbles being glassy clear. The cells are found single and in pairs, and when the wash is stirred the cells distribute themselves in a fine clay-like suspension, which clears slowly. The cells are variable in shape and size averaging 6-14 m. long by 4-5.5 broad. Spores are formed with the top yeast.

This yeast has a somewhat lower optimum temperature than the top yeast, and like most bottom yeast yields markedly less substance and is more susceptible to external factors than the top yeast. It is often found in acid washes together with the top yeast. It increases more rapidly and ferments more strongly than the top yeast at ordinary temperatures. The attenuation and yield of alcohol in pure cultures are the same as for the top yeast; it appears to leave more unfermented sugar in the dead wash. In a sample of soured cane juice having a total acidity of 2.1 per cent., and a volatile acidity of 0.90 per cent, this yeast alone was found. In the wash set up with this “acid” having an acidity of 1.6 per cent, and over 0.50 volatile, the top yeast was the characteristic worker. It would seem that in highly acid washes the more resistant top yeast gradually increases with the advance of the season. Comparative experiments with these two fission yeasts in Laboratory washes at air temperature indicate that the bottom yeast ferments the wash in one or two days less time.

A bottom yeast with slightly top phenomena has also been isolated. It forms no chains but the cells agglutinate more than the typical bottom yeast. In its properties it comes between the two extremes.

The undermentioned yeasts isolated from distillery materials play no evident part in the actual fermentation of washes.

Fruit Ether Yeast.—Isolated from ”foaming” molasses. Forms a dry white friable wrinkled film on material containing sugar. A small oval budding yeast with cells very variable in size. Forms spores on the gypsum block in 18-24 hours at air temperature. The spores are “hat shaped.” The yeast is therefore an “anomalus” variety (Willia anomala). It inverts and ferments cane sugar and will ferment diluted molasses over 50 Brix.

Produces a very high amount of acetic ether, the distilled wash containing from 12,000 to 40,000 ethers. The fermentation is slow occupying two weeks or more to attenuate 12. In ordinary washes it is easily displaced by more active yeasts. (See second S.E.S. Report, and experimental data in Laboratory records).

Pastorianus Yeast.—Isolated from “foaming” molasses. A top fermenting yeast which forms spores abundantly on the gypsum block in 18 hours. Will ferment diluted molasses of 50 Brix. Inverts and ferments cane sugar but is easily surpassed by the oval budding yeast and fission yeast in appropriate washes. It yields a fermented product of good aroma and has been used successfully in the preparation of orange wine.

Torula from Molasses.—Does not form spores and cannot invert and ferment cane sugar. A small chained oval or spherical yeast which ferments the glucose in molasses of the highest gravity. The cause of “foaming” (see second S.E.S. Report)

Large celled Oval Yeast.—A spore-forming top fermenting yeast which works badly in estates’ washes.

Ludwig’s Yeast—Found occasionally in small amount in fermenting cane juice and also present in “acid” (Long Pond and Swanswick). Is probably present on the cane. Corresponds in size, division, and spore formation to Saccharomyces ludwigii.

Mycoderma Species.—Commonly present as grey and white wrinkled films on dunder, sour skimmings, and dead washes which are allowed to lie two or more days. Produce no fermentation, but oxidize alcohol to carbonic acid and water. No spores formed.

Culture Media.—The medium which had answered well for the cultivation of all yeasts is a cane juice peptone broth. Prepare as follows:— Fresh cane juice is tempered with milk of lime, heated to the boiling point and filtered. Care must be taken to avoid excess of lime or the liquor will darken excessively. This liquor may be transferred to a Carlsberg Can and boiled for half an hour on two successive days to sterilize it.
The medium has the composition:—
tempered cane juice 100
peptone 0.5
potassium phosphate 0. 05-0.1

The cane juice should first be diluted to 13-14 Brix. The broth is heated in the steamer and filtered and then rendered distinctly acid with Hydrochloric acid or Lactic acid. The acidity should be between 0.05 and 0.1 per cent. If not clear the medium is allowed to stand a day and filtered again. It is distributed into Frendenreich flasks (a few o.c. in each) and sterilized by heating ½ hour in the steamer (Koch’s) on three successive days.

To prepare a solid medium 1.5 per cent, agar is dissolved in the broth. The medium should have a more or less pale sherry tint and should not be reddish brown.

Media containing dunder are very dark and difficult to clear. The acid of dunder affects the solidifying power of agar. 10 to 15 per cent of gelatin may be used instead of agar but cultures must then be kept in the cool incubator at 20 to 22 C. The yeasts grow much better in the cane juice medium than in a purely artificial one. The oval budding yeast retains its vitality well in the cane juice broth for over a year. The fission yeasts die out more easily but living cells are present in fair numbers after twelve months.

Fermentation experiments are carried out in flasks containing 1 litre of wash and plugged with cotton wool. Washes with an acidity exceeding .7 per cent, are generally sterile after ½ hour steaming. The progress of fermentation is determined by daily weighing, the loss being taken as carbonic acid.

The following factors are determined in all experiments (Laboratory or distillery).

The wash should be quite dead and the yeast well settled. If yeast is suspended the spindle gives a reading 0.15 to 0.4 too high. After 48 hours the reading will be correct. The weight of sugar fermented is very closely double the loss of weight.

On estates the Arnaboldi or Jamaica Saccharometer is still frequently employed. It is corrected for 80 F. and gives a reading roughly half as high again as the Brix spindle.

Sending Yeasts To Estates.

At the start of crop the distiller gets a spontaneous fermentation in whatever liquor he can get. This is either skimmings, cane juice of low gravity and purity (rum cane juice) or, if he is fortunate, fresh juice from the first mill. Dunder left from the preceding season is often used to mix with the juice. This dunder often contains matters which inhibit or interfere with the growth of the yeast. It is improved by vigorous boiling with or without the addition of lime. As soon as he has molasses and fresh dunder he can set up a normal wash. If he has to start on skimmings they often contain very little or very feeble yeast, and easily get spoilt by bacteria which render them ropy or viscous. Much difficulty is therefore often experienced in getting a good start to fermentation. In any case the yeast which develops is the oval budding kind. If “acid ” is made and used from the outset in quantity the oval yeast frequently works badly and gives place gradually to the more suitable fission yeasts. In the meantime there may be loss by bad attenuation and accumulation of materials.

In sending yeasts to estates at the start of each crop the object of the Laboratory had been to get in suitable yeasts from the outset and curtail the period of uncertainty. For estates not making “acid” the oval budding yeast, and for estates making acid—one or both of the fission yeasts.

Yeasts were sent to a few estates in December 1907, and January 1908, to still more in December 1908 and January 1909, and to over twenty estates in December 1909 and January and February 1910.

The following estates got yeast this crop:—

Yeasts are required from the middle of December to the middle of February. The estates taking them later had really started weeks earlier. The number of Common Clean Estates willing to test the yeasts could doubtless be doubled for the crop 1910-1911. They would need to be circularized in November.

Preparation Of Yeasts For Estates.

The yeast is first grown in the Frendenreich flasks in the cane juice broth. Two or three transfers should be made when fermentation has almost ceased; ½ c.c. suffices after shaking up the liquor. This is done with sterile pipettes in the glass chamber after washing down the latter with 2 per 1,000 mercuric chloride solution,; 5 c.c. are then added to 60 c.c. sterile wash in small Pasteur flasks. After fermenting in these flasks for 3 to 4 days they are shaken up and the whole liquor poured into flasks plugged with cotton wool containing 1 litre sterile wash. When fermentation has nearly ceased these flasks are shaken and the liquor poured into large flasks containing 10 to 12 litres sterile wash. The wash is allowed to die completely and the yeast permitted to settle out (24 hours after wash is dead). The covering liquor is then poured carefully away and only sufficient left to give a thick muddy suspension when the yeast is is shaken up with it. The mixture is poured on to moistened filter paper in Buchner funnels and the moisture drawn out as effectively as possible by means of the Geryk air pump. The yeast and the filter paper are lifted out, wrapped in dry filter paper with a covering of glazed paper, packed in a small tin with cotton wool and mailed by Letter Post to the Post Office nearest the estate without delay. The estate must be advised to get the yeast working on the day of arrival.

The washes in the Pasteur, litre, and large flasks should, for preference, be set up from a mixture of molasses, dunder and water, using 1/3 to 1/2 dunder (according to its acidity and gravity). The gravity of the wash should be such that it will attenuate 12 if allowed completely to die. The Pasteur and litre should have added to them 0.2 per cent, asparagin, and the wash in the large flasks 0.1 to 0.2 per cent, ammonium citrate or ammonium sulphate. In the absence of molasses muscovado sugar or concentrated cane juice may be used. If neither dunder or molasses are available the wash may be set up with muscovado sugar and citric acid (1 per cent, of a gravity of 12 Brix). To this should be added .2 per cent, asparagin for the Pasteur and litre washes, and .2 per cent, ammonium citrate for the large flasks, .05 per cent, potassium phosphate should also be added.

Before adding the yeast the wash should be warmed to 30 C. The litre and large flasks should be packed round with saw dust or better fibre packing to keep up the temperature and make the fermentation more uniform. The flasks containing the litre washes should be weighed daily to judge if fermentation is vigorous and normal. If a yeast is to go to several estates within a short period a little may be kept back in the large flasks after decanting off the dead liquor and this will serve to start another large flask (or more than one). Before sending away, a little of the yeast should be examined under the microscope to observe if it is true to its type and free from living bacteria.

Directions For Working The Yeasts On The Estates.

Set up ten gallons of fresh wash in a clean keg; the wash to consist of dunder 1/3 molasses and water, and to be of such a gravity as to give an attenuation of 12-13 Brix (18-19 Arnaboldi) if the wash were allowed to die completely. The temperature should be 86-88 F. Stir in the yeast, cover the keg and allow to stand in a warm place. When this wash has lost 9-10 Brix (14-15 Arnaboldi) by attenuation, stir up properly and pour the entire liquor into 50 gallons fresh wash. When this has attenuated to a like extent stir up and pour the whole into 500 gallons freshly set wash. When this is working well (after 24-36 hours) make up to 1,000 – 1,200 gallons. A freshly set 1,000 gallon wash can be started again from that by adding to it 50- 75 gallons when the attenuation has fallen 9-10 Brix and after thoroughly stirring up. The yeast can be got through the distillery more rapidly by keeping back 10 gallons of the fermenting 50 gallon wash and using it to start a fresh 50 or 100 gallon wash in the same puncheon (with the head knocked out) which may be poured into 1,000 gallons when it has attenuated 9-10 Brix. Skimmings should not be used in setting up wash except in the last 500 gallons.

When circularising the estates they should be asked if they propose to use “acid” in the coming crop. Content, Kent, Cinnamon Hill. Running Gut, Ironshore, Gale’s Valley, and Swanswick have already employed the top fission yeast with success. Catherine Hall, Albion and Parnassus would be best suited with the oval budding yeast. Sevens, Spring, Appleton, Denbigh, Bog and Llandovery, Green Park and probably the Belleisle Estate Co. might get both oval and bottom fission yeasts. Orange Valley should get both fission yeasts. If two yeasts are sent together the distiller should be advised to grow- them separately in 10 and 50 gallons and then pour the two 50 gallon washes together into 1,000 gallons of ordinary estate wash. The yeast better adapted to the conditions would then get the upper hand.


Acetic Bacteria.—Forming a film on liquors containing alcohol oxidizing it to acetic acid. They can be isolated from dead washes, “acid,” etc., by means of cane juice peptone agar to which 2 per cent, of alcohol has been added. The commonest forms are B. kutzingianum (or an allied species), B. xylinum and B. xylinoides. The first named does not give the blue stain with iodine. It forms a blue to white delicate very friable ascending film and clouds the liquor strongly. (For experiments with this species see second S.E.S. Report and Laboratory records). B. xylinum develops the characteristic tough thick white skin on any nonfermenting liquor containing cane sugar and not less than 10 per cent, proof spirit.

B. xylinoides forms a very similar skin on “acid” and liquor containing over 10 per cent, proof spirit. One or more of these species are always present in fermenting cane juice or estate washes and cause a rise of acidity by forming gluconic acid from sugar. When the wash is dying and especially when it is dead they produce acetic acid.

Saccharobacillus pastorianus has also been found in fermenting washes and especially in soured skimmings and cane juice. It is present as long narrow rods often covered with small particles of matter deposited on them from the liquor. The liquor is strongly clouded and the bacteria cause the appearance of silky waves. This organism grows freely in the presence of alcohol and therefore increases with the yeast during fermentation. In cane juice broth it gave rise to 0.8 per cent, total acidity of which 30-35 percent, was volatile (acetic). The fixed acid is lactic acid.

“Acid. “—This is prepared either from skimmings or cane juice by allowing them to ferment and sour in special cisterns. As a rule trash is added to the liquor which on some estates is pumped into a succession of cisterns in each of which an increase of acidity occurs. The acidity of the ripe acid rarely exceeds 2.5 per cent, and of this as a rule less than 1/3 is volatile. The highest volatile acidity hitherto observed was 0.9 per cent, out of a total acidity of 2.1 or about 43 per cent. The liquor is fermented by yeast (oval or bottom fission) and the acid increases rapidly at the same time. This increase frequently stops attenuation when several per cent, of sugar is still present. Hence “acid ” shows a most variable gravity according to the relative activities of the yeast and bacteria. The amount of acid formed is the same whether attenuation has been good or bad. (See data in Laboratory records on Swanswick “acid.”) The trash not only infects the liquor with bacteria but increases aeration. It also seems to carry on a strong infection when fresh juice is added. No marked film forms on the acid so that the acetic bacteria do not have a chance to unfold their full oxidizing activities. B. xylinoides, B. xylinum and Saccharobacillus pastorianus have been isolated from ripe acid.

The acetic bacteria form gluconic and acetic acids. The Saccharobacillus form lactic and acetic acids. The fixed acidity preponderates. (See first and second S.E.S. Reports.)

Jelly and Slime forming Bacteria.— Certain species readily form jelly and slime in weakly acid liquors containing cane sugar. Skimmings and cane juice often undergo a viscous fermentation with the production of gas and the skimmings may frequently be drawn out into long threads (ropy skimmings). This condition interferes with the yeast fermentation which is prolonged and incomplete.

The liquor shows the presence of small cocci single, paired and less frequently in chains. The viscous or ropy condition of the liquor is due to the very diffluent cell walls of the bacteria. The acidity produced in cane juice does not exceed 0.3 per cent, a trace of which is volatile. The growth on cane juice agar is very moist and slimy but no slime is produced on ordinary glucose agar. In glucose broth the chains are very marked so that the organism is a true Streptococcus.

Growth is very rapid in cane juice at 27-40 C. A nonslimy variety has also been isolated. The condition is most marked at the start of crop in both cane juice and skimmings and is due to dirt from the cane and the mill. Owing to its slimy capsule the Streptococcus is not destroyed during tempering in the clarifiers. Thorough cleaning of gutters and skimmings boxes and diluting the hot skimmings with cold water have successfully checked this condition.

Rice Grain.—This occurs not infrequently in washes on estates where no acid is employed. The wash becomes almost filled with gelatinous spherical grains about 1 mm. to 2 m.m. in diameter. The fermentation by the yeast is prolonged and often incomplete. It is caused by a rather thick rodshaped bacterium 1.5-3m by 1 m. Three varieties of this organism have been isolated (see Laboratory records). It strongly resembles the Bacterium vermiforme of Marshall Ward (ginger beer plant). In cane juice the acidity does not exceed .2 per cent. It grows rapidly at 30 C. and just as well in cane juice with 6 per cent, of alcohol by volume as in cane juice without alcohol.

It produces no change in litmus milk and grows out into long more or less cocoid chains without gelatinous sheath in glucose broth. It probably enters the wash from the skimmings.

This organism evidently does not injure the yeast by means of its chemical products. Its interference is physical as the gelatinous masses attach themselves to the yeast cells and grow over them excluding the yeast from contact with the liquor and preventing the cells from rising and whirling in the wash, a condition necessary for active fermentation. A similar kind of interference must be attributed to the streptococcus of viscous ropy skimmings or juice.

Termo bacteria, B. subtilis and B. mesentericus vulgatus have been found in cane juice. These motile forms have not been closely investigated.

The ethers varied from 30,653 to 46,030, and consisted almost wholly of acetic ether. As the ether was formed at the expense of alcohol the yields must be regarded as satisfactory particularly that for the molasses wash to which ammonium sulphate was added. The acid of dunder appears to have an injurious effect on this yeast. Chemical esterification in such liquors could not account for the enormous amount of ether produced. It is evident that both alcohol and acetic acid are formed in the yeast cells by the enzymes, zymase, and oxydase (the latter probably the same enzyme as the oxydase of the acetic bacteria) and are at once brought into union by another enzyme, the whole process occurring within the cell. Certain acetic bacteria are known to yield a vinegar containing a marked amount of acetic ether while other species are quite unable to do so. A yeast is also known which oxydises alcohol to acetic acid and some nonfermenting mycodermas are capable of producing acetic ether in alcoholic liquors. The cells of some species contain, therefore, only the oxydase, others both oxydase and ether producing ferment (esterase). Some of the mycodermas and acetic bacteria which form films on dead washes in Jamaica distilleries may esterify in the way indicated although such forms have not as yet, been isolated in the Laboratory.

Experiments With Fission Yeasts In Dunder And Concentrated Cane Juice Wash.

The juice was boiled down to the consistency of thick syrup without any tempering. The dunder was derived from cane juice and dunder washes from which all alcohol had not been distilled out. This dunder, therefore, had undergone some souring, and was rather high in volatile acidity.—

The yeasts were first grown in a mixture of the cane juice and dunder without added water in sterilized flasks containing 1 litre.

Bottom and top fission yeasts were employed. The wash died in 6 days with bottom yeasts; the wash died in 7 days with top yeasts.

The yeast sediment was then added to 10 litres in large flasks: —

The bottom yeast washes were again dead in 6 days, and the top yeast washes in 7 days.

In this experiment both bottom and top yeasts gave identical attenuations and yields. In spite of the high volatile acidity (45 per cent, of the total) the washes were rapidly (6 and 7 days) worked down with little residual sugar and with excellent results on attenuation and sugar fermented. The rums were high in ethers. Even when distilled as soon as the wash was dead, the rum contained 971 ethers and when the dead wash was allowed to lie six days they were increased to 1404. In washes high in volatile acidity considerable esterification occurs during actual fermentation, and is again greatly increased when the dead wash is allowed to lie.

Grown in pure culture in sterile wash, the top yeast does not yield a rum of higher ether content than the bottom yeast.

Experiment With Poor Dunder.

Washes in litre flasks were set up with dunder water and muscovado sugar.

Oval and fission yeasts were used; the same amount of yeast was added to the sterile wash (in 1 litre flasks) in cash each. To some flasks 10 c.c. of 10% asparagin solution was added at the outset. The loss in weight day by day was as follows:—

The fermentation was normal active with both oval and  fission yeasts in the presence of asparagin. In the absence of asparagin the yeasts scarcely multiplied and the fermentation was very feeble. When, however, asparagin was added on the third day to the latter cultures multiplication set in, and 48 hours later they were fermenting strongly.

These results show clearly that washes set up with a poor dunder are often deficient in nitrogenous food for the yeast with the result that attenuation is feeble and incomplete. In practice such washes are quickly overrun by bacteria, show rapid increase in acidity and become still more unsuited for a vigorous yeast fermentation. In the experimental distillery washes set up with similar dunder worked and attenuated very feebly; 24 hours after addition of 0.15 per cent, ammonium sulphate (equal to 15 lbs. per 1,000 gallons wash) they began to work vigorously and showed a normal attenuation.

Distillery Experiment.

The following experiment selected from a number of such carried out in the Experimental Distillery in 1908, will show what the Jamaica fission yeast are capable of yielding under well regulated conditions.
The fission yeast was of the bottom fermenting type.

It was first developed in a molasses and dunder sterile wash in a flask containing 12 litres (nearly 3 gallons). The yeast was then added to 10 gallons of similar wash in a keg after sterilizing the latter with superheated steam and cooling it to 86 F. When fermentation was almost completed in the keg the contents were stirred up and the liquor added to 50 gallons fresh wash (not sterilized) in a puncheon. When fermentation has started a further 50 gallons wash was added and fermentation allowed to proceed till the wash was quite dead.

The was dead in from 4 to 5 days.

The wash was divided into two portions; the first was distilled for high and low wines (the retorts also receiving charges of wash). The high and low wines were used in toto to charge the retorts for the second distillation 42 gallons wash being introduced into the still.

Taking 6 gallons of rum for every 1° attenuation per 1000 gallons wash as an ordinary average yield 80.4 gallons rum would have been expected on that basis; the actual yield was however 7 per cent, in excess of that amount and must therefore be regarded as highly satisfactory. The above yields are expressed in imperial gallons. In terms of wine gallons the figures are 1-5th. higher, viz., ordinary average yield 96.5 wine gallons. Actual yield 103.2 wine gallons.

Observations Of Estate Materials.

The following determinations made on materials at the estate and on samples at the Laboratory illustrate the composition of dead washes, dunder, and “acids” produced in some “Common Clean” distilleries where rums are made containing 900—1200 parts of ethers per 100,000 alcohol. On such estates no “flavour” is employed so that the ethers in the rums consist wholly or almost wholly of acetic ether.

The acidity of the ripe “acid” varied from 1.9-2.4 per cent, and the gravity from 3.5-10 Brix.

The “Rice Grain” Bacterium.

This organism with remarkably gelatinized cell walls has been already referred to as causing trouble in “common clean” washes particularly in distilleries where only fresh materials are fermented and no “acid” is made.

A sample of dead wash containing the organism was after appropriate dilution plated out in cane juice peptone agar. After some days a variety of colonies including those of yeasts appeared in the medium. Three different types of more or less gelatinous colonies of bacteria could be distinguished.

1. Of no particular shape, raised into a mass and breaking through the agar by rupturing it. These colonies at the surface were smooth, milky, dull and pasty and easily rubbed into a milky homogeneous suspension in water. Such a suspension showed under the microscope small flat, or irregular spherical gelatinous grams about 18-20 microns in diameter and free from any tendency to coalesce with each other. The flat grains showed a more or less circular outline with alternating deep and shallow depressions as indicated in the figure. Embedded in the jelly near the ends of the arms formed by the main depressions and transverse to the surface were two more highly refracting rods separated by the secondary depressions. The almost spherical grains had a convoluted appearance with a fundamentally similar structure, the rods being also transverse to the surface at the ends of the involved arms. This condition was evidently the final state of development of the grain. The resultant appearance was due to the division of rods with gelatinous cell walls, having the property of gelatinous thickening on one side particularly.

The rods are coloured yellow by aqueous iodine in iodide with darker staining granules; the jelly is hardly tinged. The aniline stains colour the rods intensely but do not affect the jelly. The individual rods vary much in length especially in the spheres where they are elongated into threads exceeding 10 micron. The minimum length is 1.5 microns and the breadth about 1 micron. In cane juice peptone broth the organism increases to a finely granular loose deposit in three days at air temperature but multiplies markedly more rapidly at blood heat. The deposit is easily brought into suspension by snaking whereby the minute flocks (grains) are rendered just visible to the naked eye. The liquor overlying the deposit is practically clear. The liquid culture shows a similar appearance under the microscope as the agar material.

Perfectly free rods are not to be found, hence the clearness of the overlying liquor. The organism grows as rapidly and abundantly in cane juice broth containing 6 per cent, alcohol by volume as in broth free from alcohol. The increase of acidity in the broth (equal to 0.1 per cent, at the beginning) does not exceed 0.25 per cent, and only a trace of this is volatile. The acid formed is probably lactic. Gas production is absent or doubtful. In litmus milk the organism produces no change in fourteen days. In nutrient broth and in glucose broth (containing 0.5 per cent glucose) growth is slow with formation of a flocky white deposit. Under the microscope long chains of short rods (almost coccoid) are visible without gelatinous envelopes. The chains grow out from the rods embedded in the grains of the inoculation material, the individual cells being 1.2-1 .5 microns in diameter.

2. Spheres with rough (facetted) surface, translucent, shining, and gelatinous like the agar. The spheres break through the agar and split it into radiating rents. The masses are at least 1 Millimetre in diameter and as a rule from 1-2 m.m. The whole sphere can be lifted away on the loop of the platinum needle. In water it cannot be reduced to a homogeneous suspension but breaks into fragments of jelly. Under the microscope the fragments of jelly are very irregular. The structure is however, very similar (though greatly more irregular) to that of the grains of No. 1. The rods are either transverse at the ends of gelatinous arms or they may be equally gelatinized on both sides. By the rupture of the jelly, the rods often project freely. The length of the rods is very variable, long threads up to 50 microns being frequent. The diameter like No. 1 is almost 1 micron.

In cane juice peptone broth this organism increases by the formation of large irregular masses of jelly or by a gelatinous deposit difficult to raise and then breaking into lumps of jelly. The liquor is distinctly cloudy which is due to the presence of large numbers of free cells with or without gelatinous capsules. The cells are often paired and also form chains of three to ten or more cells. This form also grows equally freely in juice containing 6 percent, alcohol and behaves quite similarly to No. 1 in litmus milk, nutrient broth and glucose broth. The increase of acidity in cane juice broth is also under .25 per cent, and growth at blood heat likewise very rapid.

Grown in conjunction with a bottom fission yeast, both organisms increase freely and the fermentation is 1-2 days more prolonged than in pure yeast culture. The physical interference of the organism with the yeast has been already referred to.

3. Colonies on the surface, transparent, convex, watery (mucoid, not ropy), entire, round and shining. Where colony has broken to the surface a central gelatinous mass, showing under the microscope similar but less marked gelatinous fragments as No. 2 with rods similarly embedded.

The watery part of the colony under the microscope shows rods, single paired and chained with or without an indistinct gelatinous capsule equally developed all round the cells.

In cane juice broth the organism forms an abundant translucent deposit and the liquor is still more cloudy than with No. 2. When shaken up the liquor becomes opaque due to an abundant homogeneous suspension. The dimensions of the rods are the same as for 1 and 2. Its behaviour in litmus milk, nutrient broth and glucose broth is also quite similar. In cane juice broth with 6 per cent, of alcohol the growth was less rapid than in the broth alone. The increase of acidity in cane juice was also under .25 per cent.

The appearance of the colonies applies also to the cane juice agar slants. On this medium each of the three types shows its characteristic growth. It is evident that the three forms are varieties of the same organism. In No. 1 the development of the grain is much more limited than in No. 2. In No. 3 the jelly is less robust and more diffluent, and may be compared with agar which has lost its property of solidifying by heating in a strongly acid liquor. Reference has already been made to the strong resemblance particularly of variety No. 2 to Bacterium Vermiforme of Marshall Ward.

Orange Wine.

Enquiries from several sources came to the Laboratory in the autumn of 1907 and again in the spring of 1908, as to the best way of making orange wine by direct fermentation of the sweetened juice. No experiments had at that time been carried out in connection with the orange wine making and there appeared to be no literature on the subject. The so-called orange wine on the market appeared to consist of diluted rum flavoured with orange essence (or the essential oil from the rind), and highly sweetened. This was more in the nature of a cordial or liqueur and could not be regarded as in any way a true wine.

A preliminary experiment was therefore started in March and April 1908.

A bottom fermenting fission yeast was selected to carry out the fermentation owing to the known resistant properties of fission yeast in general. In order to acclimatize the yeast to a liquor containing a high proportion of citric acid it was first grown in a mixture of molasses, water, and citric acid; the composition was—

The yeast attenuated this wash in four days to 2 Brix, and while it was still working 100 c.c. was used to start a fresh wash prepared from orange juice.

The orange juice was obtained by squeezing the juice of ripe oranges with the rind entirely removed, through a linen cloth.

Gravity of juice—13.8 Brix.
Acidity of juice—1.08 per cent.

To 1,500 c.c. of this unsterilized must, in which cane sugar had been dissolved was added (as stated above) 100 c.c. of the fermenting wash containing the fission yeast. The gravity fell in 7 days from 23.5 to 0.5 Brix, and the final acidity was 1.18 per cent.

After allowing the greater part of the yeast to settle out, the still very cloudy wine was decanted off and bottled. The bottles were filled almost to the corks which were sealed with paraffin. The bottles stood at air temperature for 8 months during which the wine had become perfectly clear and of a dark sherry colour.

The wine had a pleasant aroma of orange and an agreeable though rather marked acid taste. The palatability of the dry wine was improved by the addition of 10 per cent, pure white cane sugar. After this addition the wine was readily appreciated when drunk alone and was also found to be very refreshing beverage when consumed with the addition of two parts of Soda Water. It was pointed out, however, that this wine was not so strongly flavoured as that made by orange growers, and this was attributed to the fact that the oranges had not been squeezed with the rinds still on. The usual practice was to cut the entire oranges into quarters and squeeze out the juice in a wooden press operated by hand. In this way a part of the essential oil contained in the outer rind was set free and entered the juice. To this juice it was customary to add a small proportion of lemon juice (a sample showed a gravity of 10.4 Brix and an acidity of 3. 25 per cent.) to improve the flavour and increase the acidity. White albion sugar was then dissolved in the juice until the gravity was raised to 22-24 Brix. To get this must fermenting a “starter” was then added.

This was prepared by mixing muscovado sugar with warm water to a gravity of about 15 Brix and allowing this to set up a spontaneous fermentation occasioned by the cells and spores of yeasts contained in the sugar. As soon as this was working strongly it was poured into the orange must. If a successful fermentation was set up in the must the latter worked for one to two weeks and finally stopped before all the sugar was worked out, or was intentionally stopped by decanting off the liquor from the yeast deposit. It was pointed out that this method of fermenting the must had some disadvantages namely:—

1. The “starter” spoiled the natural flavour of the wine owing to the characteristic taste of the sugar used.
2. Fermentation often failed in the must after the addition of the “starter” or the fermentation rapid at first fall away quickly and left a product containing insufficient alcohol and too much sugar. This cleared badly and often turned sour (vinegar).

A pure culture yeast acclimatized to orange juice at the Laboratory appeared therefore to offer the most promising solution to the problem. The fission yeasts, well suited to acid distillery washes do not give a pleasant aroma to fermented must. On the other hand a pastorianus yeast isolated from molasses was found to yield a product of very agreeable aroma. It has therefore been employed in the experiments detailed below. Some preliminary work with this yeast indicated that one or more substances contained in the rind of the orange exercised an injurious effect on it when present in the juice from the outset. Juice was accordingly prepared from the fruit after removing the rind. When fermentation was active the liquor obtained by squeezing the rinds separately was added in order to increase the flavour of the finished product.

The yeast was first grown in a wash of molasses, citric acid and ammonium phosphate, then in a mixture of that wash with increasing amounts of orange juice and finally added to the orange juice must. The juice as squeezed from the fruit showed—
Gravity—11. 85 Brix.
Acidity—1. 12 per cent.

The gravity of this juice was increased to 20 Brix by the addition of white crystal sugar, and 0.1 per cent, ammonium citrate added. To start this must one-tenth its volume of a fermenting juice was added which had been attenuated by the pastorianus yeast from 19 Brix to 8.3 Brix. Two days after fermentation began one-sixth of its volume of liquor squeezed from the rinds alone was added. The gravity fell from 20 Brix to 0.3 Brix in 11 days and the must was then dead. After the bulk of the yeast had settled the wine was bottled and kept at air temperature for 15 months. An examination of the perfectly clear dark sherry coloured wine after that period yielded the following figures:—
Acidity—0.64 per cent.
Alcohol as proof spirit—21.43 per cent.

The wine had a fine sherry like aroma and was very palatable after the addition of 10 per cent, cane sugar.

Another must fermented by the same yeast a week later was set up from a juice of—
Gravity—12.05 Brix.
Acidity—1. 18 per cent.

Sugar was added to raise the gravity to 20.8 Brix. This must underwent a more prolonged fermentation and ceased to work with an appreciable amount of sugar unfermented. The must attenuated from 20.8 Brix to 2.8 Brix in 24 days. It was then bottled and cleared very slowly. Fifteen months later the perfectly clear wine showed:—
Total acidity—1.10 per cent.
Volatile acidity—0.15 per cent.
Alcohol as P.S.—18.57 per cent.
In aroma and taste it scarcely differed from the other wine.

When fresh juice is allowed to ferment spontaneously it works slowly and finally dies before all the sugar is fermented. A white dry film usually forms on the surface consisting of mycoderma or a species of Monilia while Apiculatus yeast is often abundant in the deposit. The Apiculatus yeast can only ferment the invert sugar and leaves the cane sugar untouched. As the juice contains about half the total sugar as cane sugar the attenuation stops half way.

A juice worked for 6 days and attenuated from 11.85 to 6.45 and went no further. In another portion of the juice a little added fission yeast reduced the gravity from 11.70 to 1.75 Brix owing to the power of inverting the cane sugar.

When used in larger bulks (10-15 gallons) of sweetened orange juice prepared by pressing the oranges with the rind on, the pastorianus yeast has several times failed to yield a satisfactory fermentation, results which raised the question as to whether this yeast is really well adapted for working in sweetened juice as usually set up. Fermentation certainly sets in more rapidly and vigorously if the sugar is previously melted in hot water to a consistency of syrup and then raised to the boiling point after the addition of 5 per cent. citric acid. This causes the inversion of the bulk of the sugar. The first experiment indicates that the fission yeasts work readily in sweetened juice and it will probably be safer to employ such yeasts in spite of the fact that they do not yield such a good flavoured wine.

The data set out in this paper must be regarded as of the pioneering order and should prove useful as a start in the solution of the difficulties connected with the making of genuine orange wine.

Orange Vinegar.

This is a product with which the wine maker has often hail involuntary acquaintance. About 2½ gallons of an excellent vinegar have been made at the Laboratory in the following way:—
Juice was extracted from the fruit freed from rind.
The gravity was:—10.6 Brix.
Acidity—0.80 per cent.

To this was added sugar inverted by boiling with 2% citric acid. The gravity of the sweetened must was 16.5 Brix. It was pitched with the pastorianus yeast. After 9 days the liquor was dead and showed a gravity of 0.5 Brix. It was allowed to stand in a large flask with a loosely fitting cotton wool plug. After a few weeks an acetic film developed on the liquor and after a further month this had broken up and the liquor was fairly clear.

The total acidity was—5.35 per cent.
Volatile acidity—4.0 per cent.
equal to nearly 5 per cent, of acetic acid. The vinegar was rendered practically clear by filtration through cellulose (filter or blotting paper pulped in water).

Yeast Cultures In Cane Juice Peptone Broth.

Inoculated 20 May, 1910. Frendenreioh flasks.

1. Beer yeast from Jorgensen’s Laboratory, Copenhagen maintained in cane juice broth at Hope. Sets up a speedy fermentation after 12 months in the broth. Used in top fermenting breweries in Denmark. Has been employed successfully in Kingston in a wort of brown sugar, hops and water.
2. American whisky yeast—same source—dextrin fermenting power not tested.
3. Sacchs. thermantitonum—same source—an oval building yeast, with an alleged high optimum temperature for both growth and fermentation. This strain shows nothing striking in those respects.
4. Bottom fermenting oval buckling yeast—the typical yeast of cane juice and washes of relative low acidity. Has been sent to estates in 1908, 09 and 10.
5. Top fission yeast—has been three years in culture. Isolated from a Bluecastle wash. This culture has been used for supplying estates in 1908, 09 and 10.
6. Bottom fission yeast—three years in culture; originally from Mesopotamia wash. A typical bottom yeast.
7. Bottom fission yeast with slight top phenomena from Friendship wash—three years old. Has preserved its power of vigorous fermentation better than No. 6. Has been sent to estates as “bottom yeast” in 1909 and 1910.
8. Bottom fission yeasts—isolated in spring of 1910 from a sample of Swanswick “acid.” Its fermenting power not yet tested in 1 litre portions of wash.
9. Bottom fission yeast—from Long Pond “acid” in Spring 1910. Not yet tested.
10. Top fission yeast—from Long Pond wash, 1910. Not tested.
11. Top fission yeast—from Swanswick wash 1910. Not tested.
12. Sacchs. ludwigii—from Long Pond “acid” 1910 apparently top fermenting.
13. Same as 12—from a different plating.
14. Chained budding yeast—fron Swanswick “acid”. Not investigated.
15. Narrow oval budding yeast—from Long Pond “acid.” Not investigated—may be a variety of No. 4.
16. Pastorianus yeast—from molasses—three years in culture. Used in “orange wine” experiments.
17. Budding yeast—from Parnassus and Moneymusk discoloured crystal sugars. Very abundant in sugars. May be a Torula identical with the torula causing foaming of stored molasses. Does not ferment cane sugar.
18. Willia anomalous (“Anomalus” fruit ether yeast) three years in culture from molasses. This culture was used in experiments with the fruit ether yeast.
19. Mycoderma sp.—from Long Pond dead wash.
20. Mycoderma sp. mixed with B xylinoides—from Swanswick “acid” (See remarks on “ester formation”).
21. B. xylinoides—from Long Pond ”acid” About 1% alcohol was added to the broth.
22. B. xylinoides—from Swanswick “acid.” Alcohol added to broth.
23. Oval yeast and Rice grain variety 2.
24. Large oval yeast—three years in culture.

Literature Of “rum” And “fermentation.”

Rum.—Literature very scanty.
In Library:—
Uber Brauntwein .. Eugene Sell.
Articles by P. Greg (Mesopotamia Estate) in Bulletin Botanical
Department, Jamaica.
—Vol. 2. pts 3, 8, 0.
—Vol. 3. pt. 1.
Sugar Experiment Station Reports 1 and 2.
Bulletin Dept. Agr. (new series) Vol. 1. Xo. 1.
Bulletin Dept. Agr. (new series) Vol. 1. No. 3.
Regarding “artificial rum” see
—Rum Arrack etc., by Gaber.
—Report Whisky Commission 1908.
Fermentation —

Dr. Harris Eastman Sawyer, Architect of the Modern New England Rum style?

Not many production specifics are known about New England rums besides the fact that we liked it a lot and drank a ton of it. Mountains of scholarly works exist from other rum producing regions, but no technical documents exist (especially regarding fermentation) on New England rum besides Peter Valaer’s Foreign and Domestic Rum, 1937 which is an extensive survey (but lacking in specific areas). New England rum, like all rums, transformed from a rustic product created with little regard for science to a modern industrial concern with an agro chemist as architect of all their systems. The transformation happened at the turn of the century.

While digging, I just came across the name of Dr. H. Sawyer while searching for another agro chemist. Dr. H. Sawyer was Harris Eastman Sawyer (A Harvard guy, not MIT like I had previously thought). Sawyer was likely the architect of modern New England rum when he worked for Felton & Son’s. He provided the science that sculpted the style and allowed production to scale upwards dramatically to be among the largest in the world when New England rum went through a period of consolidation. Sawyer doesn’t seem to have been in the sugar scene of colonial researchers exchanging letters and bulletins from Java to Jamaica. He was more in the scene of American analytical chemists like Crampton, Tolman, and Peter Valaer.

It is worthwhile to single out and recognize Dr. Sawyer because the product of his work and its reputation is a large part of what has inspired a new generation of New England distillers to pursue rum. Acknowledging history can guide them either to historical production standards, so we can drink a day in the shoes of our ancestors, or along the path of progress which is the downplayed culture of the distilling industry. Sawyer as we will see in the glimpse of his life that follows was an astoundingly capable chemist. He was among the referees for new analytical techniques put out by various chemistry organizations. This means when you see numbers quoted for categories like fusel oil calculated by the Allen-Marquardt method, Sawyer was among the group of chemists that duplicated, critiqued, and vouched for the new methods.

I remember Warren Winierski, of Stag’s Leap wine fame, reflecting on the 1970’s and saying “fine wine was born in the laboratory” (as opposed to commodity wine which ruled the day). Winierski went on to explain that a style could only evolve and be sculpted with chemical analysis. Winierski, Mike Grgich, and all the other kings of Napa were all lab guys. All the same ideas apply to distilling, particularly rum, the most malleable of all spirits, and who could take it further than a chemist as capable as Dr. Sawyer?

The emphasis of the lab is also reinforced by all the technical works coming out of Jamaica. The tariffs & taxes in both England and on the continent for imported spirits were so high, sometimes four times what the spirit cost to produce, that the only way to stay relevant was to produce a product so extraordinary it was worth the egregious fees. This was high ester rum and it led to quests to advance fermentation science.

Lets take a look at the life of Dr. Harris Eastman Sawyer and start with an introduction in his own words:

In ’99 I was employed by the Trade Chemists’ Co., a New York concern doing business as tanners’ consulting chemists, as manager of their Boston laboratory. I left them toward the end of 1900, and opened a laboratory of my own on Federal Street, where I divided my time between taming bacteria and making tan analyses. About a year later I agreed to give all of my time to one of my clients; and shortly afterwards I closed my city laboratory, and moved over to his rum-distillery in South Boston. I have been there ever since.

I was married in February, 1899, to Ellen Margrethe Warberg, whom I had met while living in Copenhagen, in 1897. A year later, a daughter, Margaret, was born to us. She is still our only child.

In 1901 we went home to Denmark for a three months’ visit, and since that time nothing of any account has happened. Occasionally I get away from Boston for a few days, to attend the meeting of some scientific society or for a trip to the mountains. Regularly during the spring and summer and fall I get “up river ” or into the woods on Sundays and holidays to make up for the hours which I have to waste in the laboratory and distillery.

I never have had time nor strength to take any part in public life, but I have managed to do a good deal of chemical research work in connection with technical problems in the distillery and with the food work of the Association of Official Agricultural Chemists. Once in a while I publish a paper in the Journal of the American Chemical Society. I belong to that society, as well as to others in England and France, and I am also a member of the Economic Club of Boston. Social clubs do not appeal to me.

Sawyer was employed with Felton & Son, maker of Crystal Springs rum in South Boston.

Sawyer published three scholarly articled that are in the American Chemical Society Archives (I will track them down soon and look at their bibliographies to see what he was reading):


I tracked these three papers down and the bibliographies all point to the scene of analytical chemists which was distinct from the cast of characters in the sugar scene. Sawyer is a fantastic writer and his papers, though dealing with weighty science, are notably organized better than average. He was probably a fantastic teacher.

An earlier scholarly work from his Harvard days was On Mucophenoxychloric Acid (1894)

Sawyer was even indexed in American Men of Science A bibliographic directory:

Sawyer, Dr. Harris E(astman), 244 Columbia Road, Dorchester, Mass. Chemistry, Bacteriology. Portland, Me, April 3, 68. A.B, Harvard, 91, A.M, 94, Ph.D, 95; Copenhagen, 96-97. Consulting chemist, 97- Chem. Soc; Soc. Chem. Indust; Ass. Chim. de Suc. et de Dist. de France. Methods of saccharimetry.— Graduation of Ventzke saccharimeters; methods of determining reducing sugars in cane products; detection of adulterants in distilled liquors.

We can hear even more about his career history in his own words (1899):

Writes: ” After receiving my Doctor’s degree from the University, in 1895, I spent the larger part of a year in the private laboratory of Professor Wolcott Gibbs, at Newport, where I worked upon a variety of chemical researches.

I was appointed to the Kirkland

Fellowship in the spring of 1896, and went abroad in the summer for study; I was in Copenhagen until June, 1897, working upon the chemistry of fermentation.

On my return to America, I opened a laboratory in Boston for zymotechnical work; the examination of malt, yeast, beer, etc.

In March, 1898, I became manager of the Boston laboratory of a New York concern; and I now am carrying on my own work in connection with theirs, at 620 Atlantic avenue. ” I became engaged while I was living in Denmark and was married last February. ” Was lecturer at Harvard in 1897-98.”

Sawyer’s knowledge of chemistry was pretty spectacular and he was definitely capable of doing more than running a distillery. He also worked as a referee for the development of many new analysis techniques and seems to have been an insider regarding the latest and greatest in fermentation and distillation chemistry.

While working at Felton & Son’s distillery, and also acting as an associate referee, Sawyer wrote this Report on Molasses Analysis. The report came before his American Chemical Society article on the same subject. He also participated in the Report on Distilled Liquors by the very notable C.A. Crampton whom co-authored the most notable study on whiskey of the era. In the document, there are details of how someone would work as a referee on a technique and be sent samples to test and report back on. They made sure all work was duplicatable in ways that we don’t commonly see in science today.

Harris Eastman Sawyer died in July of 1911 as noted in the Proceedings of the American Chemical Society.

Science also had a brief death announcement:

DR HARRIS EASTMAN SAWYER AB AM Ph D Harvard assistant chemist in the Bureau of Chemistry until he removed to New Hampshire on account of pulmonary tuberculosis the author of contributions to the chemistry of sugar and alcohol died on July 5 aged forty three years

A longer obituary describes his life in more detail. Apparently he contracted tuberculosis during an experiment:

He was the son of Frederick Sawyer of Gorham. Me., and Harriet Eastman Merrill of N. Conway, N. H., and was a Civil War soldier. Shortly after his marriage moved to Boston, Mass., where he has since made his home. The death of his wife, April 7, 1910, was a great blow to him. He died Feb. 11, 1913. Both are buried in Pine Grove Cemetery, Portland, Me.
I Harris Eastman, b. Apr. 3, 1868: d. July 5. 1911.
He graduated at Harvard University in 1891. The degrees of A.B., A.M. and Ph.D. have been conferred upon him. Went abroad and while pursuing studies in chemistry under traveling scholarship from the college, at Copenhagen, Denmark, he met the girl whom he subsequently made his wife. She descended from the German royal family. Dr. Sawyer in 1908 entered the government service as an expert on the subject of fermentation, under Dr. H. W. Wiley. He contracted a disease of the throat, in some of his experiments, which resulted in his death at East Andover. N. H. His widow with her daughter, Helen Margaret, b. Jan. 16, 1890, returned to her people in Denmark, where they now reside.

A notable article on Sawyer appeared in the United States Tobacco Journal, 1907, which is worth extracting in its entirety:

In the Manufacture of Tobacco.
Dr. Sawyer’s Most Interesting Exposition.
[Special to the U. S. Tobacco Journal.] WASHINGTON, D. C., Feb. 19, 1907.

A matter of much interest to the tobacco trade came before the Senate Committee on Finance during a recent hearing on the denatured alcohol bill. Frederick L. Felton, the largest distiller of rum in the country, and Dr. Harris E. Sawyer, a prominent chemist, both of Boston, advocated the use of denatured rum in the manufacture of tobacco. At present the alcohol or rum, for it is more a raw or crude spirit than alcohol, cannot be denatured and used except at 180 proof. The rum manufacturers and apparently the tobacco manufacturers also, want to be permitted to use the rum at 150 proof. Dr. Sawyer stated that the use of alcohol is an essential feature in the manufacture of many brands both of smoking and plug tobacco. In order to carry its solution many gummy materials are added for the purpose of binding tobacco to be made into plugs. More or less is used in the lubrication of machinery and in cleansing floors and the presence of a certain amount of alcohol during manufacturing processes tend to prevent the formation of mold on moist tobacco leaves. Heretofore the manufacturers of rum added a proof of 100. In the crude molasses alcohol there are certain bodies not alcohol themselves. Even as a chemist Dr. Sawyer did not pretend to say what they were because “We simply do not know.” Their amount is so small that chemists are scarcely able even by analyses to estimate their proportion. They are bodies of a waxy nature, Something like cocoa butter and when the alcohol evaporates they are left behind on the leaf. Mr. Sawyer pointed out that if the alcohol is redistilled from a proof of 100 degrees up to the proof of 180 degrees as under the existing regulations, this wax is taken out absolutely and thus We despoil the material which we supply to tobacco manufacturers of a constituent which has been shown to have a very distinct value to them. They were unable to add this material to the denatured alcohol because they did not know exactly what it Was. He said it was this wax which keeps the tobacco from drying out and makes it smoke sweeter. They have made a number of experiments on tobacco and it had been found that after several months the tobacco treated with 150 proof alcohol packed better in a pipe than that prepared with 180 proof. Furthermore, the crude alcohol at 150 carried a variety of odorous compounds derived partly from the molasses and from chemical changes which take place during fermentation. These bodies are ethereal and like the wax they seem to be retained in the tobacco after the alcohol itself has evaporated and develop there an agreeable fruity character which fails to appear when a high proof purified alcohol is substituted for the crude medium proof product. They also resemble the Wax in being removed from the crude spirit when it is redistilled from 150 up to 180. These fruity odors which develop on the leaf, said Mr. Sawyer, are considered to be very largely responsible for the character of certain brands of smoking tobacco, and while the manufacturers are very anxious to get the benefit of the remitted tax to which they are unquestionably entitled under the act of June 7th, they desire equally to hold the present character of their brands and they wish therefore to be allowed to use the crude spirit denatured at 150 degrees rather than the pure alcohol at 180 degrees. He states as an interesting fact that practically none of the alcohol is retained in the finished tobacco. In one case the tobacco having been soldered in tin cans there were traces of alcohol present in the proportion of about one-half a gallon to a ton of tobacco. He had about fifty customers among the tobacco manufacturers and supplied fifty or sixty other dealers in spirits.

Dr. Sawyer maintained that under the definition of alcohol in the Revised Statutes, the commissioner of internal revenue had authority to permit alcohol to be denatured with tobacco extracts at proofs as low as 140 or 150 degrees, but the commissioner thought otherwise. The cost of the denaturant was a cent a gallon for strong alcohol and about half a cent per proof gallon. This attracted much interest from members of the committee and they went into the subject at some length. Senator Hansbrough thought nicotine could be used as a denaturant for alcohol to be used as an aluminant for fuel purposes. “That is the cheapest denaturant I have heard of,” he said. Dr. Sawyer agreed with him, saying it is the cheapest and in many respects the most nearly an ideal denaturant. He thought it as fully efficient as any of the general denaturants that have been recommended. He did not think wood alcohol was nearly as efficient because when mixed in proportions called for under the regulations it does not impart nearly the nauseating character to the denaturized alcohol that nicotine did. It made it smell worse and might give the man undertaking to drink it more warning perhaps but the final effect on the drinker would not be nearly so pronounced as that of the nicotine denaturant. Great things are expected of denatured alcohol. It is freely predicted that in a few years the consumption will be increased to several hundred million gallons per annum and there will be a demand for denaturing agents. It would seem as though nicotine might be used in a great many cases and there would eventually be an opening in this line of business. The prospect of the passage of the bill amending the free alcohol act does not appear to be very good at this time. The bill has gone through the House and is pending before the Senate Committee but there is great opposition to it from the dis. tillers and the ether manufacturers.

A mention possibly related to the above article appeared in the Proceedings of the Twenty-Third Annual Convention of the Association of Official Agricultural Chemists held at Washington, D.C., November 14-16, 1906

Mr. Sawyer requested a somewhat broader standard for rum than he had earlier
recommended, in view of certain experiments now in progress at the distillery where
he is engaged.

Sawyer’s role as a Bureau chemist was starting to pay off for Felton & Son’s which was starting to leverage the connection for business gains.

A lot more detail on Sawyer’s rum based denatured spirit is explained in Industrial Alcohol, Sources and Manufacture.which was revised by him under H.W. Wiley, the chief of the Bureau of Chemistry. It seems like this kind of work kept Felton & Son’s well positioned to weather prohibition. Did Felton and Sawyer both feel it coming like other people did? I bet they did!

So far I haven’t found any of Sawyer’s lectures on fermentation given at Harvard or his presentations given on rum to the agricultural and chemical societies. The best look at his teaching style and sophistication come from the above linked document. He was not describing the massive ethanol plants that would come later in the century, but rather simpler small scale farm ethanol plants producing spirits from a wide variety of substrates. One that caught my eye was the potatoes of Maine.

The document (alt PDF link) provides some clues to how Sawyer might have conducted fermentation at Felton & Son’s:

Almost invariably cane molasses needs only to be diluted and yeasted to enter into vigorous fermentation. It is common however for molasses distillers to add a certain amount of acid to the fermenting solutions to prevent bacteria from invading them and setting up false fermentations. In some cases sulphuric acid is used for this purpose as in the beet molasses distilleries, but it is equally common and probably wiser to use sour distillery slop to produce the desired acidity.

This basically describes the use of dunder, but under the name “sour distillery slop”. How significant is this note? Well it just means they were modern and aware of fermentation kinetics.

Farmer’s Bulletin 410 (p.24) has more information on the state of yeast in America in 1911. Pure cultures are described and selecting yeasts with certain characteristics. Budding yeasts are described but not fission which was part of Jamaican inquiries. One notable thing described was the creation of a “spontaneous hop yeast.” This yeast culture actually involved hops and I recollect debate in the bourbon world on whether hops were ever actually used in Bourbon distilleries. If they were, this becomes the likely context.

So Sawyer was a spectacularly capable scientist. No doubt able to bring New England rum into the modern era through in depth systematic experimentation. The fact that the distillery employed him at all showed that they were interested in advancing their production.

Hopefully soon I’ll be able to take a peak at the Crystal Springs archives and see if his name comes up in the surviving documents.

Jamaica Rum with the Honorable H.H. Cousins

Sponsor my distilling work simply by sharing the artisan workshop of the Bostonapothecary on social media. Copy, Paste, Support!

I’ve cried wolf many times, but this is the most amusing and requisite paper on Jamaican rum I’ve come across. It delves into all the politics and economics then even manages to explore some of the tasting terms used by brokers of Jamaican rum in their glory days. Herbert Henry Cousins was a character and noted for writing in a “lucid style” by Nature in 1910:

H. H. Cousins, Jamaica’s first director of agriculture, was also a post card collector. Parts of the collection can be seen here.

I still have yet to cover Ashby, by then the trail seems to get cold even though H.H. Cousins was the director of agriculture into the 1930’s. I suspect World War I interrupted some of the research and then there was also secrecy. As I’ve noted in other posts, every rum producing country watched Jamaica. As their progressed advanced in controlling rums flavor, their need for secrecy increased. Other countries were catching up and that was economically significant.

Something really unique is how Cousins put in perspective the capacities of the North side distilleries. He even singles out a single firm. Because their fermentations lasted multiple weeks, they needed staggering fermentor capacity relative to still capacity. These ratios of capacity might give clues to what New England rums were like. We know New England favored column stills and distilled at very low proofs to get a full flavor, but were their fermentations long enough to get a full flavor? And could they possibly have been fermenting with a top fermenting fission yeast as opposed to a bottom fermenting budding yeast? I keep getting closer to finding out.

Government Analytical and Agricultural Chemist, Jamaica.

To deal with this matter in a manner adequate to its importance, and up to the standard of thoroughness to which the members of this Conference are accustomed in the treatment of the subjects brought before them, would involve a communication of such length as to be beyond all reasonable limits on this present occasion. Subject to Sir Daniel Morris’ approval, I have in preparation another paper, for publication in the West Indian Bulletin, in which the general subject of rum is more fully dealt with, and a summary of the outcome of the investigations that have been made upon it by the officers of the Sugar Experiment Station in Jamaica, together with a report prepared by the late Fermentation Chemist, Mr. C. Allan, B.Sc, of his observations during his three years’ study of the micro-organisms of rum, are presented.

I now propose with your kind indulgence to attempt a brief description of the miscellaneous types of sugar-cane spirit included under the generic name ‘Jamaica rum,’ and to illustrate this by submitting a series of typical samples for your examination.

As in all special industries, we have our trade secrets in the manufacture of Jamaica rum, and it is notorious that the rum trade is one of the most jealous and unapproachable of business interests.

It would not be fair, therefore, to attempt to disclose before such a gathering as this, any special secrets which it has been our lot to discover in the course of the investigations into the problems of rum manufacture, that have been made in Jamaica during the past three years. At the same time, I do not fear the competition of the other sugar-producing colonies with Jamaica in the manufacture of rum, and I am satisfied that the planters in this island have everything to gain, and very little to risk, by the fullest possible inquiry into all branches of the rum industry. Jamaica rum is, to a large extent, the natural outcome of local conditions that are apparently unique, and it is not to be expected that the laborious and slow minutiae of a high-flavoured rum process could ever form pare of the industrial working of a large sugar factory in Cuba or in British Guiana.


To understand the wide differences in the quality of Jamaica rum, we must first recognize that there are three distinct classes of rum produced in the island, each adapted for a particular market, and each judged by a different standard of excellence.

To answer the question—’ What is a good Jamaica rum?’ involves a second inquiry: ‘To what class of Jamaica rum do you refer?’ The three classes are as follows :—
(1) Rums for home consumption, or ‘local trade quality.’
(2) Rums for consumption – in the United Kingdom, or ‘home trade quality.’
(3) Rums for consumption on the continent, or ‘export trade quality.’

Each of these grades of rum meets the requirements of a special market, and is judged by a different standard of quality. I would particularly urge that these three markets, being self-contained, do not compete one with the other, and that the idea that the producers of export quality are thereby prejudicing the sales and commercial success of the ‘home trade ‘ qualities is entirely without foundation.

So far as I have been able to arrive at the facts, the commercial spheres of the three classes of rums are entirely distinct, and there is no reason to believe that the production of high-flavoured rums for blending on the continent is in any way prejudicial to the interests of the home trade Jamaica rums consumed in the United Kingdom.

Each class of rum is entirely legitimate, and there is no reason whatsoever why the makers of different types of Jamaica rum should be jealous one of the other. Again, any competition between individual estates is also without reasonable basis. Unless an article is producible in adequate quantity, and with sufficient variety of quality to enable the variable tastes of consumers to be catered for, no satisfactory trade can be developed.

With regard to the export qualities, I have received the most convincing assurance that the danger of the future of this trade lies not in over- but in under-production.


The most sensitive barometer of the material prosperity of the population of Jamaica is to be found in the Collector General’s returns of the rum duties.

Those of you who visited Port Antonio on Saturday might have observed mural notices to the effect that ‘rum ruins’ —a statement which is not open to question when the rum consumed and the cubic capacity of the consumer are to any large extent in an inverse ratio, and in favour of the liquor.

When we consider, however, that the local consumption of rum does not exceed three or four bottles per head per annum, the Jamaican cannot be charged with ruining himself with rum to any great extent.

From the point of view of the revenue and the administration of government, it is only to be regretted that our people are unable to afford the luxury of consuming three or four.times as much rum as they do at present, so that a marked reduction in taxation could be effected. While rum remains the wine of the country, so far as the lower orders in Jamaica are concerned, nothing is so striking to an observer of the habits of the upper classes, as the very large extent to which imported Scotch whisky (some of it very recent, very fiery and of very patent-still quality) has displaced rum. The high-class trade in old rums of delicate softened flavour, which were formerly so highly thought of by the planters and moneyed classes, has largely disappeared, and it would probably be most difficult to obtain a choice mark of an old rum, which has not been blended, from any spirit merchant in Jamaica today. Blends are the order of the day, and the public house trade is the chief field in which the local quality of rum is employed.

For this purpose a light rum that will age or mature very rapidly is a great desideratum. These rums are mainly produced in Vere and St. Catherine, and are the result of light settings and a quick fermentation. The stills are heated with steam coils, and double retorts are used.

The ether content of these rums varies from a minimum of 90 parts per 100,000 volumes of alcohol to about 300 parts. The bulk of this spirit would average from 180 to 220 parts of ethers. It will be noticed from the samples submitted for inspection that these rums have a delicate pleasant aroma, and when broken down with water yield a light type of residual flavour which is markedly inferior to that of the rums in Glass II.

The basis of flavour of these rums is principally due to acetic ether, while the characteristic flavour and aroma of each estate’s mark, appear to be due in every case to traces of the ethers of the higher acids, and, in a less degree, to traces of caprylic alcohol and other higher alcohols of an aromatic nature.


These are sometimes alluded to as ‘public house rums’ and represent the class of spirit which is required for the use of the spirit trade in the United Kingdom as ‘Jamaica rum.’ Owing to the strenuous efforts of Mr. Nolan, the protector of Jamaica rum in the United Kingdom, much interest has recently been shown by the retailers and consumers at home in genuine ‘Jamaica rum.’ The rums of the class to which I now refer, and which constitute the bulk of the rum exported from Jamaica, represent the type of spirit which Mr. Nolan is seeking to advertise, and to protect from fraudulent adulteration, and from the competition of spurious Jamaica rum in the United Kingdom.

It was at one time considered that an analytical standard of ethers could be fixed whereby a genuine Jamaica rum could be differentiated from a patent-still colonial rum or a blended Jamaica rum. While, however, the beat types of ‘home trade rums’ contain 300 to 500 parts of ethers, and the great bulk of the rum exported from Jamaica is well above a standard of 200 parts of ethers, there are certain marks of rum (and among them some of stout body and attractive quality) which are as low as 100 parts of ethers. Except in cases of gross adulteration, therefore, purely analytical evidence is not of much avail in deciding whether a rum be a genuine Jamaica rum or not. A proposal to prohibit the exportation of any rums below a standard of 200 parts of ethers was seriously considered by the planters last year, but was thought to be unfair to individual estates, and eventually was abandoned.

The formation of a Jamaica rum syndicate whereby a monopoly of this article is sought by a corporation to enable a higher price to be obtained has recently been effected. If the syndicate can carry through its undertakings, an increased price to the retailer of 1d. per bottle of genuine Jamaica rum would suffice to secure the planters an additional 6d. per gallon for their rum, and provide a fund of £30,000 a year for advertising the merits of ‘Jamaica rum.’

I estimate that a capital of £500,000 is required to ensure the full operation of this scheme. It must be remembered that if a puncheon of rum be sold for £10, the British revenue charges amount to £75, and the corporation will require a capital of £85 before the puncheon of rum can be dealt with as a commercial article. A large trading capital to allow of credits to publicans and other customers would be necessary. If this enterprise could be floated by interesting a large number of retailers in the shares of the company, as was done by the Guinness flotation, it is reasonably certain that a great success could be achieved.

The best rums for the home trade are made in Westmoreland, while some very fine rums are also produced in Clarendon, St. James, and Trelawney, which fall in this category.

These rums are generally produced by a slower type of fermentation than the local trade rums, and some of the best marks are produced in ground cisterns, and are slightly flavoured by the addition of some sour skimmings to the fermented materials. These rums are characterized by a high standard of heavy residual body. These are mainly ethers of acids of high molecular weight. These acids are not producible from sugars, and are almost absent in rums other than Jamaican, which are produced from diluted molasses without dunder or acid skimmings, and distilled in patent stills. Our investigations indicate that these higher acids result from the bacterial decomposition of the dead yeasts found in our distillery materials in Jamaica, and I am forced to the conclusion that the adherent yeasts in the old ground cisterns have a good deal to do with the fine flavour of many of these home trade rums.

When in London recently in the office of the leading broker who handles Jamaica rum, I was shown samples of the chief marks of home trade rums which were considered to set the standard of quality. ‘We do not want ethers, but a round rummy spirit,’ said this broker. I was pleased to find, however, that the marks selected as standards were all of high ether content (from 300 to 450 parts of ethers). They had, however, a very good standard of heavy residual body, and the blend of flavours was both mellow and full.

A trade expert in Jamaica, from whom I have obtained help on various occasions, writes me : ‘The earmarking of rum is to my idea a mistake, as any one with the least elementary knowledge of spirits knows that a blend is better than a naked spirit, always provided the blender knows his business.’

So far as the rum syndicate is concerned, there is no reason whatever why our Jamaica rums should not be blended one with another in order to get a round, full, and attractive blend; and it is to be presumed that this would be necessary in the development of the bottling trade.

The samples of home trade rums submitted have been selected from a large number as representative of this class of Jamaica rum. As compared with the local trade rums, it will be noted that they have a stouter, fuller, and more fruity aroma, and that when broken down with water, the spicy residual flavour is strongly marked.

It was impressed upon me in London by the trade experts that the planters in Jamaica should recollect that, as the duty payable on rum in England was about eight times that of its value to the planter, it was a most serious matter for the buyers at home if any fault should be found with the rum after it had been cleared from bond. Points that required attention were: (a) cloudiness on dilution; (b) a burnt flavour; (c) excessive obscuration.

We have found the chief cause of cloudiness in Jamaica rums to be due to high settings, and such an intensity of bacterial action that higher alcohols are produced in excess. The charge of wines in the retort being inadequate to fractionate these impurities, they enter into the rum and cause cloudiness on dilution. To remedy this fault, insist on the distiller testing the spirit with water before accepting it as rum. All cloudy distillate should be set aside for high wines. The fermentation should then receive attention, and, if necessary, the vats should be limed to secure a clearer fermentation.

The burnt flavour too, is common in the case of fire-heated stills. It is frequently quite unnoticeable in the sample until it has been freely diluted with water. I am convinced from the results obtained at Shrewsbury estate in Westmoreland, that all home trade rums could with advantage be distilled in stills heated by a steam coil. Burnt rum should then be unknown. The fetish of the ‘direct fire,’ that still lingers in the minds of Scotch whisky distillers has no basis at all where Jamaica rum is concerned, since any excessive firing results in a most serious injury to the spirit produced.

As regards obscuration, there is now a demand for fully coloured rums (say No. 19 on Lovibond’s scale) with an obscuration not exceeding 1¼ to 1½ per cent, of proof spirit. This is readily attainable if care be taken in preparing the colour.


Jamaica has long been famed for its rum, and a certain proportion of the crop has for very many years found its way to the markets of Europe. Thirty or forty years ago, a trade in high-class drinking rums was carried on with the continent; and I recently interviewed in Hamburg a merchant who had in former days done a good trade in choice marks of Jamaica drinking rums. He bemoaned, however, that this trade had practically ceased since 1889, when the German Government raised the duty on Jamaica rums from a very low rate to the relatively high one that now obtains, which is equivalent .to about 8¢. per liquid gallon. From that time the entry into Germany of Jamaica rums, suitable for direct consumption, has been made almost impossible. The low rates of excise on the domestic potato and grain spirits render the competition of home trade qualities of Jamaica rums with the German spirits out of the question under present conditions.

To the firm of Finke & Co., of Kingston and Bremen, and the enterprising planters of the north side of the island, belong the credit for having met this obstructive tariff by the development of a considerable trade in high-flavoured rums, of such remarkable blending power that they could stand the high import duty, and yet be utilized by the German blenders for producing a blended rum capable of competing with local distilled spirits subject to a merely nominal excise.

It is no exaggeration to say that to this enterprise alone is due the survival of the small estates on the north side, despite their great disadvantages as sugar-producing estates under the stringent conditions of the sugar market during the past ten years. There is much unreasonable prejudice against this industry among planters who are interested in home trade rums; and it has often been suggested that these high-flavoured rums are merely adulterants, and gain a profit at the expense of the genuine common clean drinking rums.

If these rums were used for blending with silent spirit in the United Kingdom, to produce blends that were sold as Jamaica rum, there would be some ground for this view; but so far as evidence can be obtained, it would appear that these rums are all used on the continent, and are not in competition with home trade rums at all.

As the only discrimination in the United Kingdom against our colonial spirit is the surtax of 4d. per gallon, there is no adequate inducement to the blenders to use high-flavoured rums at high prices for the English market.

The evidence of Mr. Steele, C.B., and of the official statistics of the German importations of Jamaica rums, all indicate that our high-flavoured rums, even when sold in London, or shipped to buyers in London, eventually pass on to the continent either in the original puncheons, or as vatted rums.

These export rums are commonly known as German flavoured rums in Jamaica, and are produced by a process that could only be adopted on a small estate with a relatively enormous distillery capacity. Instead of thirty hours’ fermentation, as in the case of a Demerara or Trinidad rum, these German-flavoured rums demand a fermenting period of fifteen to twenty-one days.

The yeasts at work are of the fission type entirely, and the whole process is operated under intensely acid conditions. It is remarkable that these fission yeasts should be able to attenuate a liquor with an acidity of 3 per cent., while the oval budding yeast may be paralyzed with an acidity of less than one-fifth of this amount.

These flavoured rums contain, as might be expected, a relatively high proportion of ethers. Some makes are as low as 600 or 700 parts of ethers, but are, as a rule, relatively rich in heavy-bodied ethers, and are possessed of great stretching power.

The finer qualities contain some 1,000 to 1,200 parts of ethers, and occasional samples may even attain a standard of 1,500 or 1,600 ethers. We have found that about 97 per cent, of these ethers are acetic ether, about 2 per cent, consist of butyric ether, traces of formic ether may be present, and from ½ to ¾ per cent, of the total consists of heavy ethers derived from acids of high molecular weight.

It is upon this small trace of heavy ethers that the chief character, and, indeed, the commercial value of a high-flavoured rum depend.

As a rule the presence of high ethers is also associated with that of higher alcohols of a peculiar spicy and attractive fragrance.

Were these rums merely dependent on acetic and butyric ethers for their peculiar value, it is obvious that our trade would be at the mercy of any and every competitor.

The higher ethers, however, have such an intensity of aroma and flavouring power that they entirely dominate all other constituents ; and the more we study the chemistry and the manufacture of German rums the more convinced do we become of the great difficulties in the way of reproducing them at will.

No two estates produce the same character of flavour. The differences are due to the variation in the bacterial flora, and these again are dominated by the differences in the composition of the material fermented, and the conditions under which it exists.

This manufacture is peculiarly precarious and erratic, both as to yields and to quality of produce. It is no unusual thing to find successive batches of rum from the same estate, apparently produced under identical conditions, varying in value from 8¢. to 4¢. per gallon. When the complicated process is studied, and the entire absence of all rational control is realized, it is only surprising that the results are not far less uniform than they are.

The trade in these rums puts a high premium on the judgement of the buyer, and the science of rum smelling is found in its highest refinement in the valuation of high flavoured rums. To attain a high measure of efficiency, long training and experience are necessary. A delicate or highly sensitive nose is not so necessary as a faculty for the memory of smells. A good flavoured rum presents to the sense of smell a blend of various distinct types of smell in a proportion that is both attractive and satisfying to the trained nose.

Ah analytical faculty must be developed whereby the ingredients may be sorted out, and approximately appraised by the trained nose under various headings.

Thus a good standard of acetic ether, associated as a rule with a high standard of ethers and intensity of flavouring power, is appraised under the heading ‘pepper’ or ‘rasse,’ that is, breed. This is best appreciated when the spirit is smelt before being diluted. Butyric ether gives a delicate fruity flavour, and rums deficient in this ingredient are sometimes described by brokers as ‘stalky.’

Homologues of caprylic ether are apparently the constituents of the pine-apple flavour; while ‘ fruit’ and ‘butter’ are other characteristic types of smell that reside in the heavy residual ethers.

The heavier ethers are more readily appreciated when the rum is diluted with an equal volume of water. This dilution at once reduces the vapour tension of the acetic ether, which then becomes greatly reduced in pungency, while the heavy oily ethers come out and assert their remarkable predominance.

We must regard the acetic and butyric ethers merely as media for the conveyance of the heavy smell of the residual ethers, and as being of very secondary importance in themselves, although constituting 99 per cent. of the total ethers in the rum.

The chemists present will, I think, concede that the chemistry of the residual and characteristic flavours of these rums is a matter of very serious difficulty to investigate, owing to the extremely minute proportions in which these intensely aromatic compounds exist in the rum.

I will now circulate for your examination a series of samples of German-flavoured rums illustrating the various types at present being produced in Jamaica.

The blenders on the continent would purchase five or six of these different rums, and blend them into a general purpose mixture, capable of being blended with silent spirit to give a blended rum of attractive style, quality, and flavour.

It would appear that the bulk of the so-called rum consumed on the continent of Europe is prepared from artificial essences, and that the trade in ‘Kunot rum ‘ has been detrimental to the interest of the Jamaica high-flavoured rum. The experiment station has been experimenting—with some success —in the direction of increasing the blending value of these rums so that they can compete on more equal terms with the sophisticated article on the continent.

An experiment has been carried out at Hampden estate in St. James to test this matter, and although the commercial results are not yet complete, we have every reason to believe that in the direction of increasing the blending power of our flavoured rums must lie the future of this industry.


Lectures on Fermentation: A Course for Distillers of Jamaica Rum (1906)

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Here we have an interesting course for Jamaican distillers in 1906 which is really a series of lectures on fermentation for distillation which happens to be what I’m focusing on now that I’ve pretty much got a good handle on still operation. Operation of the still is never really discussed, but when it is its amusing. The choice morsel refers to the honesty of distillers regarding their yields:

The usual method of gauging a distillers’ capabilities by the yield from a still, without taking anything else into account is a very objectionable one. It leads to the practice of many tricks. It has certainly been productive of many wonderful yields, and also many remarkable stills. These I believe, get less and less as the number of changes of distillers increase.

The course is by Charles Allan who followed Percival Greig. Eventually S.F. Ashby will follow Allan and give yet another view. Percival Greig, who I’ve looked at before, thought the character of rum was mainly due to yeasts, particularly a top fermenting fission yeast which he isolated. Allan on the other hand thought aromatic congeners were mainly due to bacteria. They are both right and wrong at the same time and eventually Ashby will fuse the two views. Decades later Raphael Arroyo will take it even further. I have inter library loan requests out for a mid century paper and one from the 1970’s. Hopefully their bibliographies shed light on how much attention these Jamaican experiments got. And I’m still wondering where New England was during all this and what were they reading?

Some things to note are that there is no significant mention of aging rum stocks yet and even though they are doing tons of chemical analysis they are not doing any that look at changes during aging. Allan does repeat some of his great lines from other articles:

If common clean rum is being made stick to common clean and never allow things to drift in the direction of making flavoured rum in the pious hope that you may wake up some day to find that you have become famous by making flavoured rum where it was never been made before. You are much more likely to find an infuriated Busha awaiting to tell you that your services are no longer required on that estate.

Allan speak often of economics. Even exploiting the labor and resources of a colonial outpost they were not making money hand over fist. The market was tight and distillery operators had to be well aware of the market. Spirits were commodity products and fiercely competitive. It isn’t like now where there is a fine spirits market and over inflated luxury market, trading mostly on symbolism instead of sensory values that new entrants can wiggle into.

A standout passage mentioned the German word “Rasse”.

Here again other things come in. These “other things” are difficult to define. They include body and what may be called the general character of the flavour,—what the Germans call I think, “Rasse.” These things can only be judged by one with considerable experience, but I am of the opinion that if the chemist acquired this experience he would be in a very favourable position not merely to give an idea of the value, but to render very material assistance to the manufacturer, especially in the way of assisting him to maintain a uniform standard in the article which he manufactures.

There were some notes on Rasse in the Royal Society reports:

An analytical faculty must be developed whereby the ingredients may be sorted out, and approximately appraised by the trained nose under various headings. Thus a good standard of acetic ether, associated as a rule with a high standard of ethers and intensity of flavouring power, is a raised under the heading “pepper” or “rasse,” that is, breed. This is best appreciated when the spirit is smelt before being diluted. Butyric ether gives a delicate fruity flavour, and rums deficient in this ingredient are sometimes described by brokers as “stalky.”

Here Rasse is equated with breed, and the direction German translation turned out to be race. How very German… So we’ve got a little bit more lingo of the brokers. They weren’t saying hogo in those days.

Another technical passage that caught my eye concerned the recycling of dunder and accumulation of material within it:

Again you always run the risk of leaving unfermented sugar in the wash. Indeed we have found from analysis that very few dunders are free from sugar. As this goes on sugar is allowed to accumulate in the dunder until it gets too heavy. A good deal of this sugar which is left in the dunder becomes converted into caramel, and so is lost, as caramel is unfermentable by yeasts.


There is more to come. Ashby is next and we are building up to new revelations on New England rums.

As delivered at the Course for Distillers
Government Laboratory in 1906
Charles Allan, B.Sc,
Late Fermentation Chemist, Sugar Experiment Station


You are all familiar with the phenomenon of fermentation as manifested in the manufacture of rum. You know, from your everyday experience the visible signs of the phenomenon, namely: the boiling appearance of the surface of the liquid in which a vigorous fermentation is taking place and the consequent increase of temperature. You also are aware, I have little doubt, that this boiling appearance is due to the copious evolution of gas, and that although the temperature of the liquid increases, no boiling really takes place. The name fermentation, however, probably arose from the fact that this boiling appearance always accompanied the formation of alcohol, the knowledge of which goes back to very remote antiquity.

Mistaken ideas arose as to the nature of the process based upon this appearance such as the evolution of gas from other causes. If I add a little acid to this chalk you will see that a similar boiling appearance is produced as in the case of fermentation and moreover a similar gas is given off but there is no similarity in the causes. A process, which was of very early date, was correctly associated with fermentation. This was the action of leaven in the preparation of bread. The evolutions of gas was observed in connections with the raising of the dough, though no further resemblance to the alcoholic fermentation was recognized. We know of course now that the processes are identical. The evolution of gas accompanies the formation of alcohol in the leavening of bread as it does in cases where the production of spirit is the object aimed at, only in the former instance the production of alcohol is very small.

The term fermentation first applied to the process which leads to the formation of alcohol has now a very much wider application. It includes such processes as putrefaction, the production of various acids such as Acetic. Butyric, Lactic, &c, besides many other substances. The active agents in bringing about the changes which we have described are what are called FERMENTS. There are two classes of ferments the organised and unorganized ferment. We will deal only with what are called organised ferments, that is living organisms such as yeasts and bacteria of various kinds. To go back to the fermenting vats in the distillery. When you see a liquor in a state of active fermentation you know that what is taking place is that the sugar in the liquor is being acted on by yeast with the result that the sugar is being replaced by alcohol and that gas is being sent off into the atmosphere. While this is going on the yeasts are multiplying, growing and feeding just as another plant would do.

The necessary conditions for the development of yeasts are first that there must be seed, that is, there must be some yeast cells present in the liquid before any development can take place. In the second place the liquid must be composed of such material and be in such a state as will form a suitable medium for these yeasts to thrive in, just as the soil must contain such substances and lie in such suitable condition as will allow of the growth of a plant when its seed is sown, otherwise the seed will not develop into a plant. As we will have a good deal to say about the best conditions for the development of yeasts in subsequent lectures we will leave the subject for the present. The point I wish to emphasize at present is, that there can be no development of yeast or any other living organisms without the seed or germ of such organisms being originally present. Up to the present time, at least, no single case of spontaneous generation has been experimentally proved.

This is, of practical importance as you may be assured that try as you will, you will never start a fermentation unless you have living yeast cells in the liquor which you wish to ferment. On the other hand you will not have your liquors getting bad such as becoming sour of ropy unless you get them contaminated with the organisms which give rise to these conditions.

Sterilization, as the process is termed by which a liquid may be freed from all germs, is very largely practiced in fermentation industries. In the manufacture of beer, great importance is placed upon all vessels and liquids being freed from all germs other than those which are desired to be present. In the manufacture of alcohol for the spirit only, many precautions are taken to prevent the access of undesirable germs from the fermenting vessels and the wash.

In the case of Jamaica rum practically no precautions are taken. Indeed on the other hand the distiller depends for his fermentation to start on germs which find access into the wash, accidentally. Thanks to bountiful nature and a favourable atmospheric temperature, yeasts are always about in large numbers, but it must be remembered that so are other organisms which are often of a kind which the distiller does not want.

You will readily become aware of this if you leave exposed to the air a vessel with such a substance as freshly ground cane juice, and, if you closely watch the changes which take place in the juice you will see that these changes take place in a certain order which will generally be followed in the cases where cane juice is left exposed to the air. The first change will be the familiar one of alcoholic fermentation. That is the sugar in the juice will be broken up into alcohol and carbon dioxide gas with a very small quantity of other substances such as glycerine and succinic acid. The organisms exciting alcoholic fermentation are the first to develop, because the constitution of the cane juice favours them the most. There is also generally an abundance of yeast in freshly ground cane juice from the rind of the cane. When the sugar is split up into alcohol and carbon dioxide, the character of the liquid has become changed and now a new species exciting acetic fermentation comes into play. This organism was already present in the juice, but could not make headway against the predominant yeast, because in the first place, the alcohol on which it feeds was lacking. Secondly, even had this substance been present, it could not have been utilized, because of the atmosphere of carbon dioxide immediately above the liquid preventing the free access of a copious supply of oxygen without which the oxidation of the alcohol cannot proceed. Now, however, that both substances are present, the liquid commences to undergo a second alteration, and turns sour; the acetic acid bacteria being now on the surface, and this condition endures so long as there is any alcohol left. When this is exhausted, a third group of organisms comes to the front and establishing themselves in the strongly acidic liquid consume the acetic acid, carbon dioxide and water being formed. This accomplished, the once again altered nutrient medium is attacked by putrefactive bacteria which have been carried into the vessel along with the dust in the atmosphere, but can only develop now that the alcohol and acid which are poisonous to them are wanting. The putrefactive bacteria attack whatever albuminous substances may be left and convert them into acids and other substances. More complications would in all probability take place. The lactic ferment which is always present in cane juice would succeed in developing to some extent and this would ultimately give rise to butyric fermentation, but in the end the same point would be reached. All the substances would in turn be attacked and reduced to carbonic acid and water. The distiller however, does not wish the process carried quite so far as this so he steps in on the completion of the first stage and interrupts the course of nature and separates by distillation the alcohol from the rest of the wash. The best methods of making up washes to ensure the most efficient accomplishment of the first stage, namely, alcoholic fermentation with the least, or just as much as may be desired, interference from the subsequent stages are what we wish to attain. Evidently the best and surest methods of attaining a vigorous alcoholic fermentation would be to rigidly exclude all other organisms from the wash and this would be the course we would adopt if the production of alcohol was the only consideration. Nor would this be at all difficult as the wash and vessels could be sterilized by means of steam. Unfortunately for this method, rum, and Jamaica rum, in particular, is composed of other substances than alcohol and water. The amount of the other substances are indeed very small when compared with the alcohol and water but on these other substances, small in amount as they are, depends the value of Jamaica rum and their production must not be interfered with if the high standard of this Island’s rum is to be maintained. Secondary products in Jamaica rum vary, but compared with alcohol and water would be roughly:—

As the matter of secondary products is of importance let us consider it more fully.

Suppose we take 100 gallons of rum and break it up as nearly as we can into alcohol water and secondary products.

What we are to term secondary products is composed of all the substances found in rum other than alcohol and water i.e. white rum before caramel is added.

Let us take first an average common clean rum worth about 2 / I per gallon.

In the 100 gallons rum there would be 80.4 gallons pure alcohol.

Of secondary products there would be .43 gallons or 3% pints.

Of water there would be very nearly 19 gallons.

Let us now take a good flavoured rum worth about 4/3 per gallon.

Of the 100 gallons rum there would be 78.2 gallons of alcohol.

Secondary products there would be 1.1 gallon.

Water there would be 21.1 gallons.

These two examples are taken from actual analysis of rums and the prices given per gallon were what the rums actually fetched in London.

You will observe that the difference in the analysis is mainly on the secondary products. The slight difference in the amount of alcohol is of no account.

In subsequent lectures I will show you that the chief constituent of the secondary products are ethers and will discuss with you how far a chemical analysis of a rum may be trusted as an indication of the value of the rum.

The point I wish to emphasize at present is that the value of rum depends mainly on the secondary products it contains.

I will show you by means of experiments in the laboratory that cane juice or,molasses fermented by yeasts alone produce but very little of the secondary products. These, therefore, must be formed by other organisms, chiefly bacteria which swarm in the washes of Jamaican distilleries.

You will naturally conclude that it is good to have the wash infested with bacteria. To some extent it is but unfortunately bacteria and yeasts do not thrive well in each others company, yeasts work best in liquids which are free from bacteria. It is not the bacteria themselves that the yeasts object to but the products which they form.

It must not be forgotten that alcohol is the main constituent of rum, that every gallon of rum must contain 4-5th of a gallon of pure alcohol, so that in making rum the first consideration is to produce alcohol. This can be done by encouraging the development of yeasts but in so doing you are discouraging the growth of bacteria and again if you encourage the development of bacteria you are setting up conditions which are against the interests of the yeasts. You must choose a middle course and it is just here where our greatest difficulty arises.

Such middle courses are always difficult to run. At times one or other of the sets of organisms will get the upper hand no matter what you do, and hence arises the difficulty of obtaining a uniform product, under such conditions the quality of your product must vary.

The difficulty in obtaining a uniform product has led to the reform in Beer-brewing. Under the old system the brewer found that it was impossible for him to be sure of making the same quality of beer.

In the most up-to-date breweries now not only are all bacteria excluded but yeast which has been carefully cultivated from selected seed are only used. The effect of this on the article produced was to alter to an appreciable extent its flavour but it ensured its stability in character and in a short time the newly acquired flavour got to be appreciated.

In the case of Jamaica rum however we have an article of a very different nature to deal with. The flavour is of a very pronounced character and is one of its chief assets. The flavour of beer is very delicate and is produced by the yeast itself whereas I am of title opinion that the yeasts contribute but a small amount of the flavour of rum.

There is nothing left for us then but to try the middle course and to keep in hand the various species of organisms as well as we can.

The extent to which bacteria are to be allowed to develop must depend to a considerable extent on the nature of the rum which it is desired to make. There can be nothing more disastrous to the working of a distillery than for the distiller not to know exactly what style of rum he wants to make. If common clean rum is being made stick to common clean and never allow things to drift in the direction of making flavoured rum in the pious hope that you may wake up some day to find that you have become famous by making flavoured rum where it was never been made before. You are much more likely to find an infuriated Busha awaiting to tell you that your services are no longer required on that estate.

There are certain essential differences between the manufacture of flavoured rum and common clean which if the distiller does not understand, any attempt by him to make flavoured rum on a common clean estate is almost certain to entail very serious loss in production.

Loss in production is a much more serious thing than most distillers and even managers seem to think. A penny or twopence a gallon advance in price is much more highly esteemed than an increase in production which would in the end be a greater gain to the estate.

Let us suppose you are getting a fairly good yield of rum but the price is only moderate say 2/- per gallon. If you want to increase the price of your rum you try to increase the flavour. Any attempt in this direction generally means decrease of yield but suppose you increase the price by this means to 2/2.

Then how much loss will be required to counterbalance the gain.

Take 100 gallons at 2/- = £10. How many gallons at 2/2 will you require to give you £10, result is 92 gallons. That is to say, if you increase the price by 2d a gallon but lose 8 gallons per 100 gallons in yield you are no better off than before. I do not wish to discourage you from trying to make better rum but I want to point out to you the danger you run in following the methods generally adopted for that purpose. What you want is to get to know how you can arrive at a satisfactory yield from your materials. If you can do that accurately then you could proceed to try to improve your rum without running the risk of the serious consequences of loss in production.

In this course I would advise you to give particular attention to making yourselves proficient in estimating what is a satisfactory return of rum from your washes, because without this knowledge you are not likely to make the most of your materials.


Before proceeding to speak of the manufacture of Jamaica rum let us first see what are its chief constituents. In my last lecture I pointed out to you that in the chemical analysis of rum the results were returned under three main heads, viz., Alcohol, Water, and Secondary Products or impurities. Alcohol, of course, is the chief constituent. Secondary products although insignificant in volume, are of prime importance to the value of the article. Under this head many substances are included some Of which exist in fair amounts, while others only in almost intangible traces. Before going on to explain the nature of these substances we will endeavour to get a clear idea of the meaning of the term per 100,000 parts absolute alcohol which you will always find mentioned in a Chemist’s report on the analysis of a potable spirit.

Absolute alcohol means alcohol without any water. In other words pure alcohol. It is extremely difficult to obtain absolute alcohol. The article which is sold as absolute alcohol is not really absolute alcohol at all but contains water to the extent of I % or more.

I will endeavour to illustrate to you the composition of rum by means of accurately measured volumes. Cylinder No. I. contains 1,000 cubic centimeters of rum taking the 17 bead. Cylinder No. II. contains the amount of water representing the quantity of absolute alcohol contained in Cylinder No. I.

It is on the absolute alcohol the Chemist calculates his results and he takes as his unit 100,000 parts by volume.

Now No. I. Cylinder contains the rum which we wish to analyse.
No. 2. represents absolute alcohol contained in No. I.
No. 3. represents water contained in No. I
No. 4. represents secondary products contained in No. I

We may pass over the alcohol and water without comment, as pure alcohol from whatever source obtained is the same. No chemical difference exists between alcohol from the potato and that obtained from the sugar in the cane. Pure water is also the same, from whatever source obtained.

We are left with the secondary products, and I will endeavour to illustrate by means of these small cylinders the relative amounts of the various constituents as determined in the particular sample which I have chosen.

No. I. Cylinder represents the total amount of secondary products, 10c.c.
No. 2. ”               ”                   ”                            Compound Ethers, 7.9 c.c.
No. 3. ”               ”                   ”                            Higher Alcohols, 1.3 c.c.
No. 4. ”               ”                   ”                            Acid, 1.4 c.c.
No. 5. ”               ”                   ”                            Aldehydes, 0.24 c.c.
No. 6. ”               ”                   ”                            Furfurol, 0.02 c.c.

The contents of these cylinders are not single substances in the sense that absolute alcohol is a single substance. Each of these cylinders contain substances which are very nearly related to one another as far as their chemical constitution is concerned, but they might be again divided up into several substances, each with its own characteristic properties. This will give you some idea of the complicated nature of the secondary products of rum. I am not going to speak of the chemical properties of the substances which form the constituents of the secondary products, but you have already seen that their volume is insignificant, so it is only as flavouring agents that they are of value.

First in importance, at least in quantity, are the compound ethers. The sum total of ethers is made up of acetic, butyric, propionic ether and other ethers of acids of higher molecular weight. The proportions in which they exist in rum is in the order which I have given them. Of the total amount of ether in rum, acetic ether composes at least 95 per cent, or 95 parts out of every hundred are acetic ether. Of the remaining five parts by far the larger portion is made up of butyric and propionic ethers. A small, but important part of the whole is composed of ethers of higher acids which have not been separated out and identified. The minuteness of the amount makes it almost impossible to identify those substances.

Judging from the flavour imparted by various ethers in the pure state, acetic ether gives very little flavour. It must not, however, be assumed that this ether is on that account quite useless. On the contrary, it would appear to be an essential ingredient in a good rum. It seems to act in some way as a carrier for the other ethers. At any rate a rum without a fair amount of acetic ether is flat and lacks the sharpness which is required in good rums.

Butyric ether on the other hand has a good deal of flavour. It has a heavy, fruity smell which has been described as that of pine-apples. There can be little doubt but that this substance contributes a fair quota of the flavour of rum. Propionic ether is also present in rums, and as a flavour or smell similar to what a mixture of acetic and butyric ethers would produce. Of the other ethers little can be said. That they exist in rums there is no doubt, but they are only in traces, and it is impossible to say what is the effect of each one taken separately or for that matter all taken collectively.

ACIDITY, under this term is included the acids found in rum. The acidity of a rum generally bears some relation to the amount of ethers. That is to say, that as the amount of ethers increase so does the acidity. As an ether is a compound body formed by the combination of an acid with an alcohol, you will readily understand that there is also a close relationship between the nature of the acids present and that of the ethers. The acids therefore are acetic, butyric, propionic and traces of others higher in the scale of molecular weights.

The remaining bodies, Higher Alcohols, Furfurol, and Aldehydes are usually considered under the head of ‘fusel oil,’ and looked upon as noxious. They are only found in very small quantities in rum, and although they vary in amount in different rums, yet there is no evidence to show that the variation of these substances has any appreciable effect on the value of the rum.

As far as our analysis of rums have gone the only substances which affect their value are the compound ethers. I think now planters and others interested in rum are convinced that the presence or absence of compound ethers does affect the value of a rum very considerably. On the other hand most of them are also convinced that the value does not depend entirely on ethers. The sum total of other substances contained in rum has undoubtedly some influence on the flavour. I am of the opinion that there are some substances in rum of which at present little is known. I am not speaking merely as a matter of speculation. I have observed the presence of substances other than any of those mentioned. In very small quantities indeed, but of such powerful aromatic flavour as would certainly affect to some extent the aroma of rum.

I have made no distinction as yet between flavoured rums and common clean rum. I have done this advisedly as the only marked distinction which has been found is in the quantity of the compound ethers, so that so far as the chemical analysis are concerned, the difference is one of degree, not of kind.

That a chemical analysis falls very far short of affording sure indication of the value of a rum will be readily admitted. In fact the rum merchant ridicules the idea of the chemist being able to give information worthy of serious consideration concerning the article. This is not to be wondered at when the chemical data themselves mean next to nothing. Take the amount of ethers contained in a large number of rums and let us see if we can arrive at any conclusion as to their value. The first thing that strikes one is the enormous variations in the ether figure. It varies from 80 parts to 1,800 parts per 100,000, and if we include some rums which have been made during last crop, we have a still greater range, the upper limit being 3,500. But this figure is unimportant regarded as a limit, as a much higher figure could be obtained without any difficulty if there was any object in doing so. I could easily select a list of samples which would show you a regular gradient in the amount of ethers and at the same time a corresponding rise in value, but on the other hand I could select a list which would go to prove that the amount of ethers had no effect on the price.

For instance we find that rum with an ether figure below 100 parts bringing as good a price as a rum with from 300 to 400 parts ether. We have authenticated reports of rums with 500 parts ethers selling at 2/3 per gallon. The same rum last year brought 2/2 with an ether content of 360 parts ethers. We have, however, to take into consideration the rise and fall of the market, and I do not think that we can draw any conclusion from this case.

In another instance the increase of the ethers seemed to have a prejudicial effect on the value of the rum. For common clean rum with ethers from 80 to 500 parts per 100,000 I do not think that the ether figure can be relied upon as an indication of the value. Other things seem to have just as great effect as the ethers. So far then as common clean rums are concerned chemical analysis can tell but little as to the value.

When we come to the distinguishing feature between common clean rum and flavoured rums analysis gives us material assistance. Without exception all flavoured rums are high in ethers. These rums vary in their ether contents just as common clean rums do, flavoured rums stand as it were on a higher plain as far as their ether contents are concerned. As in the case of common clean rums, the price of flavoured rums cannot be gauged by the ethers. Here again other things come in. These “other things” are difficult to define. They include body and what may be called the general character of the flavour,—what the Germans call I think, “Rasse.” These things can only be judged by one with considerable experience, but I am of the opinion that if the chemist acquired this experience he would be in a very favourable position not merely to give an idea of the value, but to render very material assistance to the manufacturer, especially in the way of assisting him to maintain a uniform standard in the article which he manufactures.


In my last lecture I spoke of the chemical analysis of rums, and what we could learn from such an analysis. We will now consider the methods of manufacture and see what we can deduce from them concerning the composition of rum.

As you know the basis of rum is alcohol, and the object of the distiller is to produce as much alcohol from his materials as he can consistent with maintaining the quality of the rum. There are therefore the factors, (let us call them) quantity and quality to be considered. For the present let us leave out of account the factor quality, and consider the manufacture of rum from the view of quantity only.

It is a well known fact that the breed of yeasts have much to do with the quantity of alcohol which they can produce. Some breeds will produce only a small quantity and then cease to act on the sugar. They do not necessarily die, but they get into a state of suspended animation. Others again produce much more alcohol before their vital activities become suspended.

The yeasts which you have to deal with are very far from being of one breed. They are many breeds, some good, some bad. I will describe some of these later, but in the meanwhile let us consider how this mixed breed acts.

The following experiment, which was carried out to see how much alcohol a mixture of yeasts such as one finds in any distillery in Jamaica would produce. In the first place it was necessary to remove all the influences which would hinder the yeasts in doing their work. A wash was made up of one part of molasses to five parts of water. This wash was thoroughly sterilized by heating it to 120° C, that is 20°, higher than the boiling point of water. A small quantity of yeasts from which all other organisms had been eliminated was then put into the wash. The wash was allowed to stand at the room temperature. The gravity of the wash was taken when the yeasts were put in. It stood at 18° Brix or 27° Arnaboldi.

When this point was reached an analysis was made of the fermented wash, giving the following results :—

Alcohol — 19.58 per cent. P.S. or 14 per cent of rum at 40 O.P.
Acidity — 0.28 per cent.
Sugar left unfermented — 0.8 per cent.
Proof Spirit per degree of attenuation — 1.08.
In another experiment made on similar lines, the gravity of the wash when the yeasts were added was 15.4° Brix. In ten days the gravity had gone down 9.50 Brix.

From these experiments you will see that these yeasts are capable of producing a very large quantity of alcohol, provided they are given sufficient time. You will note particularly that it took a longer time in the first experiment for the gravity to reach water mark than in the second. You will also observe that in the second experiment the gravity decreased much more rapidly. There is another important point which I wish you to note; that is, that in cases where yeasts freed from bacteria are used, very little acidity is formed in the wash. These experiments were carried out under what may be called ‘ideal’ conditions, but nevertheless they show how the tendency lies.

We will now take some experiments which were carried out in the Experimental distillery, which approach more nearly the actual working on Estates.

The wash was set up at 31.6° Brix on the 6th February, 1905. It was found that at this concentration no change whatever took place and the wash remained unchanged for four days. On the fifth day the wash was diluted with water to 19.1 Brix and a content of 15.6 % Sugars, with an acidity of 0.49 13 days after the wash was diluted fermentation ceased. An analysis of the ‘ dead wash’ gave the following results:—

Alcohol—9.18% P.S.
Proof Spirit per degree of attenuation—O.827

The experiments which were carried out in the Experimental Distillery and which are given in the Report for 1905 show clearly that fermentation carried on under the conditions usually found in Jamaica must yield very irregular results. From my own experience of what I have seen in the distilleries, I am convinced that the yields of rum must be very far indeed from what they might be.

I have shown you that from a wash fermented in such a way as would prevent the admission of organisms other than yeasts, a much better yield of alcohol can be got. By so doing, however, a very poor quality rum is obtained, so it is advisable to admit bacteria to a certain extent. The point is where are you to draw the line! Is there any means of knowing when the bacteria are getting too great a hold on the wash? There are certain signs which should tell a practical distiller when this is happening. The wash gets acid, the fermentation sluggish, and ultimately if things are not remedied fermentation ceases altogether. I have been on several cases asked for a remedy for sluggish fermentation, and consequent loss of yield. I have found in one or two cases the yield reduced down to less than one half what it should be. On examining the materials I always found them swarming with bacteria of all sorts. Sometimes the acidity of the wash was by no means too high, but other bacterial products were having a very prejudicial effect on the yeast. My remedy has invariably been successful, and it is simple enough, -Lime and water; lime to counteract the acidity, and water to remove the dirt. I have generally also found it advisable to recommend a reduction of the gravity at which the wash was set up.

I know there is a strong prejudice against the use of lime in Jamaican distilleries, and also a considerable reluctance to the use of water. The contention is that lime kills the flavour. I do not deny but that it does. If used in excess it will certainly kill flavour and also kill the yeast, but just as in the case of all medicines, it must be administered in proper doses if it is to be beneficial. If vats are well washed out frequently, and then washed with a thin lime wash, nothing but good will result, especially in common clean estates. Wood-ashes (I have found) are very frequently used. Their action is something similar to lime, though not so effective in checking bacterial development. It is, however safer, as you may heave in a half vat full with not much effect. Lime must not be used in such large quantities as will make the wash alkaline as then it will prevent the development of the yeast, and it will also prevent the development of certain bacteria which are essential in the production of flavour. Use lime as a wash, and I do not think you will find it doing any harm. If you are to maintain a good yield you must aim at getting a regular fermentation and attenuation, and to do this you must check and keep within limits the development of bacteria.

I am of the opinion that in common clean distilleries the yield should be the first consideration. To get a good yield there are two important points to attend to. First the setting up gravity. Speaking generally, this is far too high in Jamaica. The initial gravity in common clean estates should not exceed 15° to 16° Brix or 22° to 24° Arnaboldi. The amount of alcohol from a given quantity of wash will of course be less, but you will get more rum out of a given weight of sugar. The reasons for this are not far to seek. If you set up high you place the yeasts in an unfavourable medium, for they work slower in heavy liquids than in light ones. Bacteria are not so particular, they find heavy liquids as congenial as light. Secondly the time taken for completing the fermentation is prolonged, the yeasts get more and more sluggish and the bacteria get stronger and stronger. In distilling you get a comparatively better return from a weak alcoholic solution than from a strong.

The distiller’s reply to these arguments are that low gravities produce a low grade rum. They say that rums made from washes set up at low gravities are light in body. I have no doubt but that this is perfectly true. The reason is, that with a low gravity the yeasts work better and faster, and so do not allow the bacteria to get a chance. With high gravities on the other hand, the yeasts work more slowly, a longer time is required for the wash to attenuate, and hence there will be a greater development of bacteria. Again you always run the risk of leaving unfermented sugar in the wash. Indeed we have found from analysis that very few dunders are free from sugar. As this goes on sugar is allowed to accumulate in the dunder until it gets too heavy. A good deal of this sugar which is left in the dunder becomes converted into caramel, and so is lost, as caramel is unfermentable by yeasts.

In this case, as in others, you have to consider how far you can go in pursuit of flavour at the expense of yield. You must always bear in mind that it is not in the interest of the estate to produce flavour if by so doing the output is so lessened as to mean a net loss as against a poorer quality but a better yield. The usual method of gauging a distillers’ capabilities by the yield from a still, without taking anything else into account is a very objectionable one. It leads to the practice of many tricks. It has certainly been productive of many wonderful yields, and also many remarkable stills. These I believe, get less and less as the number of changes of distillers increase.

Another plea is often put forward for high gravities, that is, that sometimes materials increase so that they must be got rid of anyhow. This is what I would call wanton waste, and extra receivers should be provided for emergencies of this kind. Again, more time may be lost by sluggish fermentation than would be taken up in a few extra vats working off.

I cannot impress too much on you the necessity of some intelligent and fairly accurate method of calculating what amount of rum should be obtained from each vat. Without being able to do this, you are working in the dark, and you can never make such a good use of experience and observation to improve.

In the first place it is essential to have all your vats, receivers, and stills accurately gauged. It is worse than useless to guess about the capacity. A difference of 50 to 100 gallons in capacity just decides whether your yield is good or bad. I can recommend no other methods than either by measuring the contents or by weighing them. Select a vat, fill it with water, then run it into a 4 or 5 gallon measure and count the number of times the contents of the vat fills the measure. This is a laborous method, but the vats and receivers are generally so irregular in shape that they require very intricate calculations to get at their capacities, even approximately.

To calculate the approximate yield of spirit from a wash from attenuation. This is very simple indeed if you use a Brix Hydrometer which I recommend as being vastly superior to the Arnaboldi. The Brix instruments can be had from the Laboratory, and there is no reason why they should not be adopted on every Estate.

In the experiments carried out in the Experimental Distillery the amount of Proof Spirit per degree of attenuation was found to vary somewhat. It will always be found to do so, but within limits, if the fermentation is good and healthy. The limit should be .8% of proof spirit for every degree of attenuation per 100 gallons of wash. To take an example:—

The yield of spirit of that wash should not be less than .8° x 12° = 9.6 gallons proof spirit per 100 gallons of wash, or 96 gallons proof spirit from a 1,000 gallons wash. To convert 96 gallons proof spirit to strength of rum :—

96 * 5-7 = 68.5 = 68% gallons of rum at 40 over proof.

This is the lowest limit, and you should not be satisfied with it. You should aim at least at getting .9% P. S. for every degree of attenuation. Yield of spirit per 100 gallons wash —

.9 x 12° = 10.8 P. S. or 10.8 x 5-7 = 77 gallons per 1,000.

It may go as high as I gallon for every degree, then ; —

1 x 12° = 12 P.S. = 12 x 5-7 = 85 gallons per 1,000.

One gallon for every degree of attenuation is I think the highest you are ever likely to reach. In fact you will lie much more likely to fall very short of it. You should, however, not be content with anything short of .9% for every degree of attenuation.

One other point I wish to emphasize, and that is you must know accurately the capacity of your still, otherwise any calculation you may make is useless, and you will only deceive yourselves by those calculations.


In my last lecture I dealt with the yield of rum purely from the point of view of quantity and therefore confined myself to the production of alcohol. Now I propose dealing with the production of flavours in rum, and the various experiments which have been carried out in the laboratory and on estates with a view to the investigation of the development of these flavours.

Analyses of rums made in the laboratory established the fact that the compound ethers contained in the rum was closely connected with the flavour. Now these ethers are compound bodies formed by the combination of alcohol with an acid. If an organic acid such as acetic acid is allowed to remain in contact with alcohol, a certain amount of the alcohol and acid will combine and form acetic ether. If the mixture is distilled a larger proportion will combine.

We already know how the alcohol is formed so we have to find out how the acids are formed.

The organic acids found in rum are produced by fermentation in a similar way to that in which alcohol is produced. The organisms causing this fermentation are different and are of many kind. When dilute alcohol is exposed to the air, it is attacked by a ferment known as the acetic ferment and is turned into acetic acid. In order that the formation of acetic acid may go on a supply of air must be accessible as, oxygen which is obtained from the air is indispensable to the life of the acetic ferment. Thus the formation of acetic acid takes place for the most part at the surface of the liquid and when the ferment has developed sufficiently it forms a thin pelicle over the surface of the liquid. Acetic acid forms a very large proportion of the acid found in rum.

Acetic acid is the acid of vinegar. The method in which vinegar is made is interesting as, in some measure, the same process is followed in making acid on estates making flavoured rum. The wine which is to be converted into vinegar is placed in casks, half filled, at about 30 degrees C. to which air has moderately free access. The formation of acetic acid takes place in consequence of the liquid being gradually covered with a film consisting of the mother of vinegar. In other countries the German quick “vinegar process” is employed in which the growth of bacteria suspended in dilute spirit mixed with vinegar, is accelerated by coming into intimate contact with the air. This is brought about by allowing free access of air, by dividing the liquid into small drops and distributing these over a large surface (such as beech shavings.)

Acetic acid must be produced in large quantities in the distilleries of this island but especially in those making flavoured rum. Indeed in them special processes have been evolved to produce this acid as well as others. The part of the process which is mostly concerned in the production of acetic acid is the fermentation of what is called rum cane juice. This juice is generally poor in sugar and what sugar there is, is mostly glucose which would not crystallize out even the juice. It is however, in a suitable state for being fermented. A weak alcoholic solution is formed. This liquor is thrown over cane trash and allowed to stand. The result is that the alcohol is turned into acetic acid. You will note how closely this process corresponds to that of making vinegar. Only in the case of vinegar making a freer access to air is given.

Next to acetic acid in point of quantity as found in rum is butyric acid. This acid is formed by fermentation excited by many forms of bacteria. The one which perhaps forms it most readily is known as Bacillus butyricus. I have given a considerable amount of study to this organism as I found to be very prevalent in washes and materials about distilleries and especially those making flavoured rum. I have isolated this organism and grown it on a fairly large scale. In order to isolate organisms of this class they must be cultivated out of contact with air as the oxygen is fatal to them. After having cultivated them to some extent by this means I inoculated them into a 5 gallon tube and having succeeded in getting them to grow there I transferred them to puncheons. From these they could be grown in any quantity for estate experiments with butyricus. A five gallon keg of liquid was taken to an estate. The contents was emptied into a cistern of 1,000 gallons capacity. Dunder which had been made almost neutral with lime was added and about two gallons of molasses. A vigorous fermentation started. After a few days the contents of this cistern was used as dunder in getting up a wash. When the wash was distilled a heavy fruity smell was the result. On a second trial it was found that the presence of this organism had a very detrimental effect on the attenuation.

On another estate the effect of this organism was tried and it was found that it had a very marked effect on the rum. The retardation of the alcoholic fermentation was prevented by making the liquid in which the organism was cultivated much stronger in butyric acid, can always be done by neutralizing the acid formed.

By this means a flavour was undoubtedly imparted to the rum but in my opinion it is somewhat harsh and suggests too much one ingredient. It requires to be blended with something else to make it a desirable flavour. Reports on the rum are expected soon. In another experiment carried out on an estate where the butyric fermentation was stimulated by special materials a rum was produced by the High Ether process which brought 5/6 per gallon. Of course there were other organisms at work here but there was a large amount of butyric acid produced by organisms of this nature.

In putrefaction butyric acid is produced as well as other higher acids.

Putrefactive bacteria require nitrogenous substances to feed on. The albuminous matter of the cane supplies this but a more important source is the dead yeast cells which remain in the dunder. The dunder muck as it is called is almost wholly composed of yeast cells. In the dunder itself there is also a large amount of albuminous matter which has been made soluble by boiling in the still. The soluble portion goes back into the wash and assists to feed the yeasts and bacteria there. The solid dunder is used in the flavour making process on estates making flavoured rum.

As far as our analytical investigations have taken us the only result of adding flavour and acid to the wash as is the practice on flavoured estates is the addition of acids. The acidity of the wash making flavoured rum is always much higher than in washes making common clean rum.

From these data you will see that the amount of acid and especially the amount of volatile acid, which is the chief point, is very much greater in the materials which go to make flavoured rum than in common clean.

The point I wish to emphasize is that the chief difference and the only one which is measurable by chemical analysis between common clean rum and flavoured rum is the ethers and we know that other things being equal the amount of ethers increases with the amount of volatile acid in the wash. The essential difference then between the manufacture of Common Clean Rum and Flavoured rum is in the production of acids. These volatile organic acids are produced by fermentation under certain conditions and the object of the distiller is to get at those conditions which favour the production of acids which he wants.

Different organisms require different conditions these I will discuss when I speak of these organisms.

LEES.—The virtue of lees in producing flavour has been partially recognized for long but not I think to its full value. The lees from the Retorts contain a good deal of acid. On flavoured estates as much as .7 % of acid has been found. Now this acid is all volatile otherwise it would not have gone over into the retort. What happens is this, the acid distills over along with the alcohol but being much less volatile gets condensed in the retort. These lees have been made use off but I am sure much of them is wasted for want of proper storage. The process known as the high ether process has for its aim the utilization of the acid in the lees.

I have here a sample of rum made on an estate by using the lees directly in the wash instead of acid. The rum when made had a somewhat greenish smell but otherwise it was good and sold readily enough at 3/9, this being the price which the rums made on the estate were fetching at the time.

Lees have also been used I believe in the retort in small quantities. I may also add that flavour has also been used in this way. Its use seemed to have a slight beneficial effect. Lees ought to be stored for some time before use. What exactly takes place I cannot say but ripened lees as they are called have a much better effect than fresh lees.

Lees however should not be mixed with the solid dunder for some time as the lees will prevent it from decomposing. On the other hand when the fermentation of the dunder solids has gone so far the lees should be added to stop further decomposition, otherwise if the putrefactive organisms are allowed to complete there work you will have nothing at all left, as you must bear in mind the work of putrefactive germs is to reduce all the substances on which they act to water and certain gases such as Carbonic acid, Hydrogen sulphide and Ammonia. By adding the lees at the right time you stop this action and utilize the acids formed.

The only method of gauging this is by carefully observing the acidity of the material. For a time it will gradually increase, then it will cease and if left alone will begin to get less and less again. The amount of acid formed is very small but if carefully neutralized with lime the action will again start, as in the experiment I have already described. You will see how important it is that you should make yourselves thoroughly acquainted with the methods of determining acidities and alkalinity.


In my previous lectures I have showed you that the active agents in producing alcohol from sugar are yeasts, and I have also stated that the flavour of rum was due in most part to the action of bacteria. I will now describe (in more detail) to you, some of those ferments, as a knowledge of how those organisms develop and the conditions under which they thrive best, will assist you to- some extent in controlling your fermentations. Let us consider (first) the yeasts:—Yeasts are living plants. Just as much plant as the sugar cane is a plant. The differences are great, but are only in structure and size. When you look at yeasts under the microscope you may see many forms, but the essential characteristic is, that they are single cells. What you see is a thin membrane enveloping a clear transparent substance. This substance is the living matter of the plant and is called the plasma. All plants and animals are built up of cells but in the case for instance of the sugarcane, many cells are required to form one plant. Some of these cells are specialized in such a way as to suit them for absorbing nourishment from the soil, others go to build up the complicated structure known as the stem, others form leaves and others (again) go to reproduce the plant. Yeasts and all one-celled plants include all their vital functions in the one cell. They feed, grow, and multiply just as other plants do but very simply. If you watch a yeast cell under such conditions, as will allow it to grow and multiply, you will see it throw out a small bud from its membrane. This bud grows larger and larger, and in time it will break off and free itself from the parent cell. This process goes on and on as long as the conditions in which the cells are placed will allow it.

When the yeast cell is young and vigorous, the contents of the cell are clear and transparent, but when it gets old or gets starved for want of food its contents become granular, and empty spaces appears called vacuoles. In coloured liquids, such as washes, living cells can easily be distinguished from dead ones. The dead cells get coloured with the liquid while the living ones remain quite clear.

There are many kinds or species of yeasts. Some of them can be recognized under the microscope by their forms, others cannot.

We often speak of wild yeasts and cultivated yeasts. The distinction has something of the same significance as when we speak of wild cattle and domesticated cattle. There is another broad division of the yeasts depending on the way they ferment a liquor. Some yeasts work at the bottom of the liquor while others work at the top.

They are thus called top fermentation yeasts or bottom fermentation yeasts. For the most part Jamaica yeasts are bottom fermentation yeasts. In beer brewing both kinds of yeasts are used. In England the top kind is invariably used, while on the continent the bottom is used. In the case of top fermentation a very heavy foaming head is formed, while when bottom fermentation is taking place very little head is formed.

A few of the more important groups have the following characters:

Cerevisiae group.—These are the yeasts producing the normal fermentations resulting in beer, etc. They are round slightly ovoid cells.

Pastorianus group—These are wild yeasts. The cells are elongated or sausage shaped.

Ellipsoideus group.—These are also wild yeasts. The cells are usually ovoid or pear shaped. Sometimes they are round.

All these forms are found in Jamaican distilleries.

There is also another type of yeast found very largely in Jamaican distilleries. I have found it in all the distilleries but it is specially plentiful in north-side estates where flavoured rum is made. This yeast can be easily recognized under the microscope by its shape. It is a long rod-shaped cell. Its method of multiplying is quite distinct from other types of yeasts.

It does not form buds but first grows into a long rod then a division is formed across the rod and what was one cell becomes two cells and ultimately the two cells separate and form two organisms. The difference is that round forms multiply by budding while the rod-shaped forms multiply by division.

It is remarkable that this form should thrive best on those estates using very acid washes. I have not had sufficient time to devote to these forms but they seem to me to be in some way connected with the production of flavoured rum. I have made various attempts to isolate these but have not yet been successful in getting them to develop in the laboratory. What happens is that the round forms which are always mixed with the rod forms readily develop in the laboratory and swamp the others. In establishing a fermentation for flavoured rum, it is just possible that such conditions as will permit of this kind of yeasts developing will have to be obtained. This is a point which will require further study but will in time be elucidated.

Yeasts are found in the air but for the most part yeasts find their way into the wash from the rind of the cane. Large numbers are found on the rind of the cane. From the rind they get into the juice and hence into the skimmings. They are also found in the molasses but this must be by contamination from vessels as they cannot survive boiling.

To start a fermentation, cane juice slightly warmed should be used. If however, the juice has sulphur dioxide added to it for the purposes of clarification, juice should be taken to which no sulphur dioxide has been added. Sulphurous acid is poisonous to organisms, but after the juice has been boiled the sulphurous acid becomes converted to sulphuric acid which in small amount has not an inhibiting effect on yeasts.

Yeasts thrive very well in all sugar solutions and cane juice seems to be a very favourable medium for them. The action of the yeasts on cane sugar is first to convert it into glucose or uncrystallizable sugar, then to break this up into alcohol, and small quantities of other bodies such as succinic acid and glycerine. The fermentation of sugars by yeasts is a function of the living cell and everything that affects the life of the latter has a certain influence on its fermentative power. Substances which serve as food for the yeast promote fermentation. Generally speaking acids are deleterious to the cell, their influence being the more marked as their concentration is increased.

Different acids have different effects. In some cases yeasts seem to thrive in fair amounts of acid while in others a very small amount seems to influence them unfavourably.

It is stated that .1 percent, of sulphuric acid reduced the energy of fermentation while .7 per cent, inhibited it altogether. The development of the yeast-plant was promoted by .02 per cent, of sulphuric or by .1 to .5 per cent, of lactic acid, but unfavourably influenced by .07 per cent, of the former or 1.5 per cent of the latter. The volatile organic acids such as acetic butyric, etc., affect fermentation unfavourably when present in large amounts.

It is difficult to say what acidity is really the limit where fermentation is seriously retarded, it depends so much on the nature of the acids present. For common clean rum, 1 per cent, is high enough at the start of fermentation and it may go up to 1½ per cent, without doing much harm. In the manufacture of flavoured rum much higher acidities are used, but in these cases fermentation is undoubtedly retarded. The best temperature for yeast development is from 80°F to 90°F. Above this temperature yeasts are less vigorous. Higher temperatures favour the development of bacteria and hence of acids.

Bacteria.—Bacteria are the busiest forms of organic life. They are single cells belonging to the lowest forms of plant life. They vary in form and there is considerable difference in size, but species cannot be readily distinguished by their form and shape. To give you some idea of the size of these minute germs, the lactic acid ferment is 3-25,000 of an inch long and 1-25,000 of an inch wide. That is, it would require 25,000 placed side by side to measure one inch. Something over 900 billions weigh 1 grain or 1-28 of an oz. Bacteria are found every where, in air, soil, water, dust, clothes, skin alimentary canal of man and animals, and in our food. Very small quantities of organic matter are sufficient for their support, and the nature of this organic matter is very varied—carbohydrates, such as sugar and starch, all kinds of organic matter and mineral matter. Moisture is necessary; without it bacteria will not develop. The majority of bacteria like warmth, but some of them grow at low temperature. Bacteria live in temperatures between 39 degree F. and 122 degree F. Some will survive at still higher temperatures. These minute organisms are extremely retentive of life. They never die a natural death. They may be killed by various means, such as by heat, by poison, by starvation, by exposure to sunlight. It is a fact worth noting, that direct sunlight is a powerful germicide. Disease germs being […] sensitive to the […] of light. [ocr errors]

These are the chief factors which determine the development of bacteria, food, temperature and absence of sunlight.

No useful purpose would be served by my going into the biological characters of the various bacteria found in distilleries. Their numbers are legion and the species numerous. The chief ferments I have already described viz:—the acetic and butyric ferments. The latter is what is called an anaerobic organism that is, it cannot set up fermentation in the presence of oxygen, but I have found that it works well in liquids in which aerobic, that is air-loving organisms, have been first established. This is how it is able to work in liquors exposed to the air. There is a type of bacterial action known as viscous fermentation, which often gives trouble in distilleries. Lumps of a jelly-like substance are often seen floating in liquors. This viscous fermentation is caused by a particular organism which acts upon glucose, and transforms it into a kind of dextrin or gum. A similar organism causes ropiness in skimmings. The same phenomenon is often met with in the manufacture of sugar, masses of gelatinous consistency being formed. These masses are composed of microbes with extraordinarily swollen and gelatinised cell-walls which appeared as masses of jelly in which the organisms were embedded.

Another phenomenon sometimes makes its appearance in distilleries and goes under the name of rice grain. These masses which resemble grains of boiled rice are composed of yeasts closely packed together. In the liquor is found an animalcule called the vinegar eel. This eel which resembles a very small worm gets into the skimmings by means of rain-water which washes it from roofs and gutters.

As far as acetic and butyric acid fermentations are concerned, these can be controlled in a similar manner to alcoholic fermentation by yeasts. The conditions for these types of fermentation are well ascertained. It is very different when we come to consider the putrefactive process. The changes which albuminous matter undergoes when attacked by various micro-organisms are not completely ascertained at present. We know when putrefaction is taking place by the development of a peculiar and characteristic odour, partly due to certain gases such as Sulphuretted Hydrogen, Ammonia, and other gases being disengaged. This feature is especially noticeable when the microbes carry out their work in the absence of air, the process being comparatively inodourous when a free access of air is permitted. Many microbes take part in these changes but it is not known whether a particular series of changes is due entirely to one kind of organism or whether the process is started by and carried further by another; whether the decompositions take place simultaneously or successively. We know that during these changes among other substances volatile acids are produced and that these acids are among the ingredients which go to produce the flavour in rum but we do not know what other substances produced in this process enter into the composition of flavour. Moreover we can do little to control the putrefactive process. You must put down the materials and trust to nature to do the rest. We may assist putrefaction to start and we may arrest it when we think it has gone far enough but we cannot inoculate a wash for instance with cultures with any hope of producing a desired result. For this part of the manufacture of flavoured rum you must experiment with your materials until you obtain what you want. I do not claim more as the result of my investigations than that I have established the fact that the flavour of Jamaica rum is mainly produced by bacterial action and in a general way indicated the nature of the organisms at work. I have also indicated certain lines by following which you are likely to obtain flavour. From my remarks on the idiosyncrasies of these tiny forms of life which you have to coax into working for you, you will easily understand how perplexing it would be for one, who has no knowledge of them to comprehend their ways.

Organic Acid Trickery / High Ether Rum / Ether Theory

I just found another cache of interesting papers on Jamaica rum. What is interesting is that they are firmly in the 20th century and have forgotten about the great Agricola and a lot of the work that has come before them. They show the very beginnings of bacterial, yeast and fermentation science. Fermentation science is something I’ve been studying lately and its really cool to learn it from the beginning, where there are probably missteps, but its a lot less complicated. Something that emerges is that some scientists thought the character of full flavored rum was the result of bacterial action while others thought it was the result of yeasts. What we now think is its a combination of the two.

One thing that has perplexed me is where the hell was New England rum this whole time? I’m beginning to think New England rum was nothing special flavorwise and any high regard it held was nationalistic opinion. But I may be able to get to the bottom of that. Loft apartments have taken over the most notable New England distillery and the building superintendent has a closet full of their old documents. The documents may have bibliographies and possibly point to a collaboration with MIT in the very early 20th century which would likely yield work with more bibliographies. My hunch is that anything New England learned, they learned from Jamaica and any work with MIT would be about implementation and not about research which is why there are no distinct papers. Knowledge of what was happening in Jamaica appeared all over the Louisiana Planter and Sugar Manufacturer. The building super is busy adding new condos, but has promised me an eventual glimpse of what documents they have.

This document below might have been written by H.H. Cousins or Mr. Joseph Shore, but I haven’t been able to confirm that yet. It appears in a few appendixes but without attribution of the author. The patent mentioned at the end might be findable as well.

(Society paper no. 274)
Investigations of Jamaica Rum

From the report of the island and agricultural chemist, Jamaica 18th March, 1907

This work which was started in 1903 by the appointment on a three years’ contract of Mr. C. Allan, B.Sc., as Fermentation Chemist to co-operate with the Laboratory staff in the investigation of Jamaica Rum has reached the first stage in its progress by the completion of Mr. Allan’s period of service.

At the outset practically nothing was known as to the composition of the materials used and of the changes which occurred during the process of fermentation employed in the manufacture of Jamaica Rum, and Mr. Allan carried out a valuable piece of work in securing information on these points.

He was able to establish the general principle upon which the fermentation of the various products was based and to show clearly that the “flavour” of Jamaica Rum to which the great variety in character and quality of our island spirits is due was the result not of alcoholic fermentation by yeasts but to acidic and putrefactive fermentations by bacteria.

This is a fact of prime importance in the scientific study of Rum manufacture, and a further study of the chemical composition of Jamaica rums indicated that the compound ethers are the chief source of the special aroma on which the commercial value depends.

Mr. Allan summarised the results of the experiment that had been made in the Laboratory, the Experimental Distillery and on estates in a course of lectures which he gave to the distillers in October. These are to be published as part of a general publication on Jamaica rum for the use of our distillers which is now in preparation.

In November Mr. S. F. Ashby, B.Sc., late Carnegie Research Fellow and Bacteriologist at the Rothamsted Experimental Station, was appointed to take up the combined duties of Bacteriologist, and Fermentation Chemist. Mr. Ashby is devoting himself to the isolation and study of the individual organisms at work in estates’ materials and to the investigation of the comparative value for alcohol production and flavour of the yeasts and other organisms thus obtained.

It is hoped that during the next three years some valuable discoveries capable of affecting favourably the productive power of our distilleries will result from these labours.

The High Ether Process as invented by me for reinforcing the Ether Content of rum by recovering the volatile acids left in the spent liquor from the retorts and returning them into the process was carried out on a commercial scale on six estates during the crop.

On three estates making a common clean rum the process was systematically carried out to increase the standard of ethers and the whole crop was carefully regulated to a uniform standard about fifty per cent higher than that otherwise obtainable. As the materials employed were identically those resulting from the fermentation in each case, the result was simply that of an intensification of the normal flavour of the rum without altering its
character. The rums were sold in London and favourably reported upon by brokers and merchants as improved in quality. The manager of one estate gave me figures showing a net profit of £200 on the season’s operations under the process applied in this way.

It was necessary to keep this enterprise secret owing to the baseless and ill-informed prejudices of brokers and others in the rum trade against the new process. It was ignorantly supposed to be a process of chemical adulteration, and some London brokers even declared their belief that sulphuric acid was a necessary ingredient of rum produced under the process.

It should be understood that nothing passes into the rum which is not normally present, and that the use of lime to combine with the acids in the lees to enable a solid residue to be recovered by evaporation and the subsequent liberation of the acids by the addition of the requisite amount of sulphuric acid to the lime or salts, simply results in a sediment of inert sulphate of lime which is removed by filtration and the practical result is that volatile acids produced by fermentation and at present wasted are recovered and returned into the process to increase the output of ether natural to the rum in question.

It should also be understood that the process does not create flavour or impart a high flavour to a common rum but is merely a convenient practical means of reinforcing the normal flavour of a rum as resulting from the products of the fermentation by which it was produced.

On three estates the process was tried on an estate scale with high-flavoured or German rums. In one case although the rum was sold at a higher price, the general management of the fermentation was unsatisfactory and the yield so poor that the distiller was dismissed and a reversion to the old method was decided upon. The poor yield was in no way due to the process, but to attempts to produce a superior flavour and to provide the requisite supply of acid material for the production of a high ether rum, whereas in view of trade prejudices it was decided by the management to make a rum of ordinary ether standard.

This experiment threw no light on the merits of the process as applied to a high flavoured rum, and I am satisfied from experience that under favourable conditions of management the financial outcome should have been encouraging.

At Hampden Estate an excellent plant for operating the whole production of the distillery under the high ether process was erected. Thirty puncheons of rum varying but slightly from a uniform standard of 3,500 parts of ethers as against 900 for the ordinary liquor rum and 300 for the low wines rum was produced.

This product was boycotted by the merchants and brokers in Jamaica and London and was finally reported upon as “commercially unsaleable” by the London agents of the estate.

It was considered valuable by some buyers in Germany, but they were afraid to buy it because some expert pronounced it to be flavoured with chemical essences. The outlook for the proprietor of Hampden Estate who had taken up this experiment with great zeal and had carried out the process with extraordinary skill and success was so discouraging that I decided personally while on leave to enquire into the matter in England and in Germany in the course of my enquiries into the rum trade.

Having obtained a fortnight’s extra leave on half pay I visited London, Glasgow, Hamburg and Bremen with introductions from the Customs and the Foreign Office which enabled me to interview traders as an accredited Government officer. It is gratifying to be able to report that all the rum was sold as a result of this effort and that the bulk of the thirty puncheons was sold for 8s. per gallon. It was evident that the large holders of stocks of the ordinary “German” or “ Export Quality” rums viewed with apprehension a process for increasing the blending value of Jamaica rums as likely to depreciate the value of old stocks. Again, the standard of ethers in this rum being four times that of the ordinary make caused the concentrated rum to be viewed with suspicion as an artificial essence.

This experiment proved that the whole output could be turned into a rum at 3,500 ethers from the same materials now producing a rum averaging about 700 ethers (liquor and low wines rum together). In other words, the process is capable of increasing the ether content of a “German” rum five-fold.

It must be noted that the fermentation and materials were not interfered with in any way.

The financial results on the process rum were most encouraging, but it is to be regretted that the rum made by the old process after the concentrated rum was reported unsaleable at any price in London realised poor prices and I cannot help thinking was deliberately under priced in London as a result of trade prejudices.

The commercial bearings of this matter are very complicated and some years will be required before the real merits of the case can be decided.

A very interesting experiment was carried out on an estate in Vere making a common clean rum. In this case a special fermentation of flavouring materials for making acids was set up separately and this was distilled separately so as to obtain the volatile acids. These were then introduced by my process into the ordinary common clean materials and a rum was obtained of about 2,000 ethers that sold for 5s. 6d. per gallon. This was tested by blenders on the Continent and found so satisfactory that a large order was sent which could not be filled owing to crop having been completed. This is the most remarkable demonstration of the ether theory yet obtained. Rum was raised from 2s. 3d. to 5s. 6d. a gallon simply by increasing the ethers and developing a suitable fermentation of flavouring material for the supply of the volatile acids.

At the wish of the two Planters’ Associations, Patents have been taken out in my name for the benefit of the Sugar Experiment Station, should the Patents possess a commercial value, in the following countries :—
United Kingdom

As the process is applicable to Whisky and Brandy, it is possible that it might find use for reinforcing the ether content of these spirits, and that Royalties might be obtained from the foreign rights under the Patents.