Rum, Osmotolerance and the Lash

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Osmotolerance is basically the ability of micro organisms to tolerate stress. The stress comes from solutes dissolved in a solvent. Yeast stressors (or lack there of) are probably one of the most significant ways by which rum fermentations differ. In many naive cases, the stressors select the yeasts and in cases where you pick the yeasts (team Pombe!), you need to follow up with appropriate stressors (if you cannot work completely sterile). I’m probably using language biologists would cringe at, but what the hell, this is a blog.

Osmotolerance relates to the Delle stabilization concept I’ve talked about before. We use simplified rules of thumb that a wine becomes stable at 18% alcohol, but according to professor Delle, each percentage point of sugar can offset an amount of ethanol and you can start to achieve stability at far lower alcohol levels. If you add carbonation on top of both, you can start to achieve stability even lower and that may be the secret of wines like Moscato d’Asti which are often stable at 5%. The point here is that all these variables function in a system of stressors and changing one variable changes response to the others.

All these variables exist in rum fermentations and then some. Rum in most cases isn’t just one single yeast or bacteria but a varied community. Changes to the stressor matrix shifts the ability of any member of the microbial community to grow at all or even to become dominant. Schizosaccharomyces Pombe yeasts are known for their osmotolerance relative to budding yeasts and in many cases, though they have a lower frequency of occurrence, they can become dominant in spontaneous ferments. Before anyone thinks to play around and go huge hoping for greatness, remember, its easy to create a ferment so stressful near nothing beneficial grows but bacteria you don’t want and you end up with an unpredictable sluggish brew working so slowly your economy goes to hell, half the vats stick, and you quickly go out of business. Rum magic only happens when you know what you are doing so you can walk that magic line.

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.

Playing with osmotolerance is like playing with fire. Arroyo actually didn’t want to play the game and went in the other direction pioneering molasses pre-treatment and creating conditions where ferments could produce extraordinary aroma while fermenting to high concentrations of ethanol with great economy and in record time.

Arroyo went osmo-intolerant by heating to sterilize molasses just like a grain mash, but with modified pH and calibrated buffers to preserve aroma (an epic trick!). He then somehow got a hold of an Alfa Laval pilot plant continuous centrifuge (in the late 1930’s!) and clarified the molasses. This changes the stressor matrix and it also sets up the ferment to be distilled in a continuous column still where scaling is much more of an issue than a batch still. Molasses pre-treatment became a rule of thumb to anyone using a continuous still. No longer related to osmotolerance, Arroyo also employed the same centrifuge again pre-distillation to remove the lees as well as dissolved gases. From what I gather, unlike other spirits such as Cognac, Arroyo didn’t even distill heavy rums on their lees.

I recently contacted Alfa Laval and am trying to get more information on their continuous centrifuges and what exactly they sell that is pilot plant scale. They have models, seemingly small, but are for tasks like centrifuging bio diesel and not molasses. Alfa Laval sells to all the big Kentucky distilleries who centrifuge their stillage to remove water and prepare it to become animal feed. They also sell to very large breweries who centrifuge their beers to gain economy from the bottom of the vats. I have yet to find out conclusively, but I’m estimating a pilot plant continuous centrifuge for distillery tasks may cost about $30K. A barrel a day distillery would still have room to grow into their pilot plant scale equipment. That cost, only on the hunch that it is really beneficial, is very hard to swallow. They promised me more information so hopefully I can update this with something optimistic.

The big takeaway is that so many of the rums we know, love and are inspired by are the products of these very serious centrifuges. Small distilleries will have a lot of trouble going osmo-intolerant (my funny arbitrary term for opposition by the way). If a small scale, low involvement distiller says they don’t like the effect of centrifuging or any molasses pre-treatment, they basically have no clue and just need to accept their limitations when being “small batch”. Another category of rums are naive rums, endearingly produced by people who do not know their options and some of these rums are the most extraordinary and tell the best stories. Distillation requires certain scale and the new arm of the industry is slow to accept that.

As I always say, there is nothing finer than rum as we make it and no category of rum ferment is superior to another. Osmo-intolerant is the direction rums are commonly taken when pure yeast cultures are used and when economy is a large consideration. These rums are more likely to be distilled continuously and they are more likely to be lower risk over all. Due to a few other really cool reasons I’ll get to eventually these spirits will also age much quicker.

There are very few spontaneous ferments these days, but due to techniques like back slopping of yeast, exotic starters, and the usage of bacteria infected dunder, some ferments can use osmotolerance to create a sort of chaotic timbre. Stressors will effect the growth kinetics of the varied microbial community that eventually develops. The pure yeast culture that kicks things off at the beginning of the season may eventually be supplanted by a wild yeast that rises to dominance under the conditions encountered. Big windows for chaos through which we glimpse terroir, are opened by producers both consciously and unconsciously. There is risk, chance, and irrational energy, the duende!, all over the place. This category is a place for both the naive and the truly masterful. The most masterful of wrangling glorious chaos these days is probably Hampden estates in Jamaica which is known to be very significant to the Smith & Cross blend. I’ve aspired to make a similar rum, but don’t think I can do it until I really explore and master all of the analytic techniques. I request 20 years.

Stressors reduced by Arroyo style molasses pre-treatment are mainly gums and ash. The pH is also adjusted to be optimized for the selected yeast. Total sugars are increased due to the decrease in volume of the precipitated and separated fractions. Because the yeast can now ferment to higher concentrations of sugar, they can also better take advantage of the nutrients so less need to be added though they are often carefully calibrated. Dunder, on the other hand, though it leads to an accumulation of gums and ash, also brings yeast nutrients. It probably also brings nefarious copper salts leached from a copper boiler under acidic conditions, but I don’t recall seeing research specifically tied to that yet.

So dunder itself brings brings stress and relief. Many dunders were and/or are ripened to accumulate hopefully beneficial bacteria. The most desirable being Clostridium Sacharo Butyricum. The byproduct of bacteria’s metabolism is fatty acids and those can stress the yeasts by lowering the pH. They can also stress the bacteria themselves.

In the Arroyo method, the pH is carefully adjusted to remain constant, and far higher than you’d think which is possible because of the pure cultures he employed. As pH decreases, alkaline substances are carefully added to lock up the acids as salts. The acids that have the most affinity for salting also happen to be the most ordinary like acetic and formic. These ordinary (as opposed to extraordinary cough cough frequency of occurrence!) acids and their ethyl esters are typically in part separated during distillation. Having less to remove due to salting means the heads fraction can be smaller and the spirits will mature faster. Spirits going both ways with osmotolerance can benefit from the pH buffering / salting method but spirits produced using the Arroyo method are more likely to employ it.

If the pH were allowed to run away the accumulation of stressors would slow down or completely shut down various actors in the microbial community. This can be a feature or a flaw. Low pH ferments can produce lighter spirits because bacteria has less leeway to act.

These ideas were definitely not new to rum making and go back to Jamaica well into the nineteen century. The great Agricola, W.F. Whitehouse, (father of modern rum according to me) mentions how alkaline lime was introduced to Jamaica by Dr. Bryan Higgins. It became central to the operation of a muck hole. The contents would undergo putrefactive fermentation producing acids until the pH dropped too low maxing out the osmotolerance of the bacteria then lime would bring the pH back up and fermentation would restart. The process would go on and on. The locked up aromas would unlock when combined in a ferment with another acid, the most ignoble acids fortunately having an affinity for staying locked up.

But don’t forget, though salts buffer the pH, they are also a stressor and yeasts and bacteria will have different resistance to salt concentrations. Another big source of osmotic pressure is ethanol, and Arroyo reminds us we can’t just think of alcohol tolerance itself because it is always relative to temperature. Yeasts can resist the osmotic pressure of ethanol much better at low fermentation temperatures than high.

Arroyo re-imagined and re-applied all the concepts with more finesse and calculation. Not all fatty acids and not all esters are created equal and Arroyo more than anyone else at the time kept his eye on the price of creating and selecting for the most extraordinary and suave (his favorite rum descriptor). The concept of osmotolerance is at the heart of coaxing all of it out.

I’d love to work on this more but I’m out of time

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Colonial Pissing Contests with the great Agricola, W.F. Whitehouse

Where to begin? I came across the strange collected writings of a ranting, maniacal, 19th century sugar cane plantation owner and I kept reading because he was particularly funny. He kept quoting latin, corresponding around the world, following new ideas in organic chemistry, and penning fanatical letters to the editor. Then he started talking distillation, in 1843, like no one had ever talked it. Nothing to my knowledge exists like this until 60 years later when you see Ordinneau, Nettleton, and works of the Jamaican agricultural experiment station in 1905. The Coffey still didn’t really come out until 1830.

I don’t really know the exact time line of Jamaican rum styles. Did high ester rums exist already in 1843 or did Whitehouse and his culture invent them? I say culture because Whitehouse died in 1846 at the age of 75, but his spirit of inquiry certainly endured. Were high ester rums pressured into existence by the competition of Europoean continuous stills? Agricola mentions everything from plowing technologies to labor organization to biochar®, but makes no mention of full flavored rum, but then he does mention all the things necessary to lead to high ester rum’s development.

I’ve taken the original document and edited out everything but what was relevant to distillation and explaining what I guess could be called the incident. Its 26 pages but don’t worry there isn’t much science until the very end. Much of the text is about the interloping huckster, O’Keefe, coming to town. Then the pissing contest where they basically have a distill off that ends up being pretty humorous. The meditation on technique the contest inspires, leaves us with a very short easy to understand treatise on rum making that allows us to get into the mind of a probably precocious 19th century savant. If you read my other post, Muck Hole Not Dunder Pit, where I look at a text from 1905 (almost 70 years later!), you will see all the pieces coming together to create the legendary high ester style of Jamaican rum.

Maybe we should start not with Agricola but with a short dedication by Leonard Wray Esq. from his Practical Sugar Planter (1848).

The perfect realization of your Lordship’s anticipations is satisfactorily evidenced in the excellent treatise written by (the late) Mr. Whitehouse on that occasion ; for that lamented planter was so sensitive to the injustice that was done him, in the subsequent award of the prize, for which he had competed, that, in an able review of the successful treatise, as well as the others, he exposed their various faults, and demonstrated the correctness of his own views. A discussion of this nature naturally excited the attention of the planters to the points in dispute, and induced an inquiry into several improvements suggested. Thus a spirit was implanted—a curiosity engendered, which cannot fail to develop itself to the benefit of “the planting interest”.


PART 2nd.
October 20th, 1841.

Not seeing any notice of the letter of Etonian in your paper, I beg to call your attention to it; if you can find room, I would advise you to publish it for the benefit of your planting friends. I assure you it has made quite a sensation among us, generally, not easily excited planters. I was asked by so many what I thought of the letter, that I was obliged, a couple of days ago, to borrow a paper to see it. [Etonian, an Eton college alumni, here is the nick name Agricola is giving to the English interloper]

At first I was inclined to think that the gentleman had either deceived himself, or had been so by somebody else ; in fact, I did not think it was possible to get the return he stated. I have since carefully studied the subject, and find it quite practicable, so cannot doubt his having done so.

Etonian deserves the greatest credit for having shown us what we can do by good management and skill in the still house ; he, however, recommends us to carry the matter too far, which it would be, if we were to convert the cane juice into rum. I should strongly recommend planters not by any means to do so, but to confine their exertions to the legitimate object of making the largest returns possible from the means they at present possess. If estates generally were to convert a part of their sugar crop into rum, the price would fall so low as not to remunerate. In Demerara, where distillation is carried on much more successfully than here, the price of rum is so low, owing to the large crops, that it often pays them better to sell the molasses in the raw state. One estate, there, last year, made 500 puns, from 560 hhds., but a part of the cane juice was turned into rum. Let planters therefore confine themselves to making the largest returns they can from the molasses and skimmings they are at present in the habit of using. Any increase then must be clear profit.

[a Teache is a boiler used for evaporating cane juice]
Etonian is not altogether right in his description of boiling sugar,—the work is not left to the negroes, but the overseer directs the quantity of temper to be given in the clarifier, generally two-thirds of what he supposes requisite ; when the liquor comes to the second or first teache, the remainder of the temper is given; the quantity is known both by the colour of the froth in the second teache, and also from the way the liquor cuts, (as the negroes call it) in the teache, when it boils down the first time.— The head boiler is then directed to boil high or boil low, according to the overseer’s judgment. After the skip cools, if the overseer is satisfied with the appearance and grain of the sugar, he directs the head boiler to continue the same quantity of temper, and to boil the same way. In practice there cannot be much improvement made here, that is, supposing the people strain and clean the liquor as they ought, the overseer and boilers making the most of the means they possess; but there is great room for improvement in the furnace and hanging of the coppers, which ought to do the work in less than half the time they do at present. The sugar would be improved accordingly. I only want to show that overseers are not, in the boiling department, to blame for not getting as large a proportion, and as good a quality of sugar, as a chemist would expect from the richness of the liquor.

According to Dutrone’s Table, the liquor operated upon by Etonian, of 1.077 specific gravity, contains 19 per cent of sugar, and therefore 2000 gallons, which he estimates, (and which is commonly calculated,) equal to 13 cwt. of sugar, should yield, at the rate of 19 lbs. in the 100 lbs., (or 10 gallons), 3.800 lbs. of sugar. Suppose in the common process you obtain 2000 lbs., the remainder would be sweets equivalent to 1800 lbs.sugar. By the rule that a pound of sugar is resolved during fermentation into half a pound of carbonic acid gas, and half a pound of pure alcohol, which half pound of pure alcohol is equal to a pound of proof spirit, 1800,lbs. sweets should, if the process of fermentation and distillation be perfect, yield.1800 lbs. of proof spirit, or, at 10 lbs. to a gallon, 180 gallons; instead of which, if we get 80 or 90 gallons’, we are satisfied. It will thus be seen we have not approached more than half way to perfection.
[At this point in time different hydrometers were just coming out but they also knew of specific gravity using scales. I did re-invent this wheel myself when I learned to measure specific gravity with a kitchen scale and started authoring highly static recipes that specified densities. They apparently also knew of molar masses and stuff like that so they knew of theoretical yields for stuff even if they weren’t close to achieving them.]

I conceive there would be no saving in labour or fuel by converting cane-juice into rum. The value of the fuel and labour for boiling 400 gallons into sugar is just the labour and fuel necessary for our skip, (400 gallons usually making that quantity,) which takes about 1½ or two hours to boil, according to the working of the coppers. The: labour, fermenting, and distilling would be at least half-a-day, and the fuel sufficient for three or four hour’s fire, in which time as much would be consumed in the slow fire of the still as in the quick fire of the boiling house. [I think this very last comment eludes to them knowing to distill with a slow fire]

If it takes 3,000 instead of 2,000 gallons to make a hogshead of sugar, it is because the juice is not so sweet; it would therefore prove less by the saccharometer, and if converted into rum would not make more than the 2,000 gallons of sweeter liquor.
[Allan’s saccharometer was patented in 1840]


Note.—Where rum-canes are ground for the purpose of accumulating trash, the still must be run with wood; but, if the process were carried on on a large scale, the trash would have to be used for fuel under the still.

Nov. 15th, 1842.

I was much pleased, on the perusal of the proceedings of the St. Andrew’s Agricultural Society, at the project of forming a Central Board of Agriculture. A similar idea had occurred to myself, that we should have a Central Agricultural and Scientific Society at Kingston, which should be in communication with all the branch societies, and which should publish annually a volume of transactions of every matter connected with and inducing to the improvement of agriculture, mechanics, &c. ; also statistical accounts of the agriculture and geology of the island: in fact everything that can conduce to the welfare and prosperity of the Island.
[This means that we could probably see complete records of the development of high ester Jamaican rums somewhere though the Experiment Station in 1905 doesn’t seem to reference anything, but I guess I need to check again.]

The Highland Society, and the Royal Agricultural Society of Great Britain, are conducted on some such plan ; the branch societies all communicating matters of interest to the parent society to be published annually. Then being elected a member, should be an honorary distinction, the same as members of the Royal Society. I do not know the constitution or objects of the present Jamaica Society, but as I believe that most of the leading people in Kingston are members of it, it might at once be converted into such an institution with great advantage to the country. The transactions would become a volume of great interest to the community. A model farm at the expense of the country, where the nature of manures, systems of cultivation—implements of husbandry, and improved methods of manufacture might be tried, would be very advantageous, if conducted under the auspices of the Society, but I fear the state of the finances will not allow it; much good may however be effected without it. The Society might recommend those deserving of remuneration to the attention of the Legislature, and bestow honorary medals and distinctions.

I have also viewed with much satisfaction, the attempts in various parishes made by the overseers for the benefit of absent proprietors, and for their own honor, by proposing handsome prizes for increasing the crops, etc, Absent proprietors, if they know their own interests, will support them cheerfully in such endeavors, the welfare of their properties depending much more upon the exertions of the overseers, than of the attorneys ; for, however good the arrangements of the attorney may be, unless the overseer back his efforts with hearty good will, those, efforts, will not be crowned with success. Overseers are the mainstay of the island, and let them thus refute by their acts the calumnies that have been heaped upon them. They are the majority in all the societies, let them support their own interests, which they cannot do more effectually than by supporting the interest of the proprietors.

I see many prizes proposed for the benefit of the proprietor, but from the thing being quite new to us all, many of these proposals will not effect the object aimed at as well as could be wished. Let me suggest the following prizes, which I think will meet their views.

To the Overseer of the Best Managed Estate, a gold medal, or a silver cup, with a suitable inscription. To the second competitor, a silver medal, suitably inscribed.

That every estate, whether level or hilly, rich or poor, large or small, may be able to compete for it on equal terms, it is necessary to draw up rules that will suit all.

These are what I propose—

The criterion in awarding the prize to be the combination of excellence in the greatest number of the following points of good management.

1. Large amount of Sugar made in proportion to the extent of this cane-field, and the usual yielding of the estate.

2. Large amount of Rum made in proportion to the quantity of sweets employed and the strength of the spirit.

3. Small amount of wages expended for carrying on all the work of the estate, in proportion to the extent of the crop of sugar and rum.

4. General good management of the cane-field; a simple and easy method of manuring a small extent of plants in proportion to rattoons, and the least expensive’system of cleaning the canes. [Here contests emerge for advancing the state of agriculture. Its a really beautiful open idea of a high tide lifts all boats that you’ll also see on this blog. The ratoons are the new shoots of sugar cane after the crop is harvested. The root system is left intact and everything is cut with an attempt to produce a new crop as fast as possible. This letter goes on a little more but I lost it and there is a prize for improving the quality of rum which I think implies sensory quality]


For other prizes I should propose, are

To the Overseer who made the largest sugar crop from the smallest cane-field.

To the Overseer who made the cheapest sugar crop.

To the bookkeeper who made the largest rum crop, in proportion to the sweets used and the strength of spirit.

To the Overseer who introduced the best method of cultivating canes by agricultural implements, or who introduced new implements saving the greatest amount of manual labour in the field.

To the Overseer who introduced machinery at the mill or manufactory, saving, the greatest amount of manual labour.

For improving the quality of sugar.

For improving the quality of rum.

In each of the above cases, a silver medal with a suitable inscription. Regulations must be formed for the judges to decide by.

Let Overseers propose such prizes and though some attorneys may throw cold water upon their undertaking, let them carry them into effect, and they will meet with the ready support of the proprietors and of those attorneys who have the real interests of the estates at heart. [I suspect if Agricola’s advice was ever taken there would be records of it somewhere.]

December 26, 1842.

Sir,—Allow me to answer “Perfer et Obdura’s” mild and temperate letter in defence of the system of distillation introduced into practice by Mr. O’Keefe- I trust my answer may be characterised by the same good qualities which are the spirit in which, these, matters ought to be discussed. [Perfer et Obdura, from Ovid: be patient and tough and here it is used as a nickname]

My opponent is surprised that the alterations, he calls them improvements, proposed by Mr. O’Keefe, have not been sufficiently and fairly appreciated. I reply, that the plan has been tried by myself and many others in this district, with every wish and intention of carrying his objects fully into effect, more particularly by a friend of mine, an Irishman, who for the honor of his countryman was peculiarly anxious that success should attend the attempt. The plan was as fairly tried as it could possibly be, and has been given up by every body among my acquaintance, as a total failure. I had no great opinion of it at the outset : but I notwithstanding, gave it a fair trial, following his printed instructions, which must be supposed to contain the exact plan he wished pursued ; by those instructions the plan was fully and fairly tried, and failed as I before mentioned, in every instance within my knowledge. I think, therefore, that we cannot be blamed for not having duly appreciated his plan; but on the contrary, I think we are to be praised for having so long withstood publicly expressing our dissent from the practice, and for affording Mr. O’Keefe an opportunity of trying the experiment for a length of time under his immediate superintendence, without any prejudice being shown against him. His plan has been generally abandoned for months in this quarter.

Am I then averse to giving him every encouragement in his undertaking? Quite the contrary, I think he should meet with every facility. Every intelligent man who devotes his attention to, tho improvement of our staple products should meet with due encouragement. I am of opinion that Mr, O’Keefe will in time find out correct methods for increasing the return of rum; he may even now have done so, for I do not pretend to know what system he may at present adopt ; the probability is, that during the time he has been conducting the process under his own superintendence, he may have materially altered his plan of proceeding and improved accordingly, I can only speak of the plan he published about a year ago. [where can we find the plan!?] I understand he has published in last week’s Journal, testimonials as to the advantages of his system, but I have not seen them. If these testimonials prove that he is a successful distiller, they merely prove, that he is able to conduct the process himself, but unable to instruct others how to do so.
[So we need to look through the November/December 1842 issues of the Jamaican Standard]

My opponent states, that Mr. O’Keefe merely adopts the best systems practised in Great Britain and on the Continent, and that condemning those practices, we condemn the best practical distillers in the World. Now, the practices adopted in Great Britain are not by any means good; unfortunately the law steps in, and says to Mr. Distiller, “for the convenience of collecting the revenue, you must do as I order you, and not follow the dictates of your own knowledge and skill, however beneficial they might prove;” to look to Great Britain, therefore, for the best examples, is like asking a man with his hands tied behind him, to help you out of difficulty. To France you must turn for the best examples of theory and practice combined, for there the parties are unrestricted. These results you may find in Dunbrunfaut,—a work which contains all the best methods practised, and which are far superior to the English. [S. H. Hastie (1,2,3) complained of excise restrictions and it really hampered his work and that was more than sixty years later. I have not read Dunbrunfaut (1830) yet but it details the column still so Whitehouse was certainly aware of a lot]

O’Keefe it seems identifies himself with the best systems practised in Great Britain and on the Continent, and therefore condemning O’Keefe is condemning the whole host of practical distillers in the old World. It may be considered presumptuous in me to enter the lists against such antagonists; but yet I venture to affirm that the best of them would find their plans not suited to our circumstances, and would be obliged materially to modify them. I have carefully studied Dubrunfaut, and have tried the plans recommended according to the best of my abilities. At the very time that O’Keefe brought forward his first letter in the papers, I was trying them, and apparently with great success. I have, however, since found out my errors, and, as I believe, the causes of the failure.— Upon the same rock that I split, I contend that O’Keefe (according to his printed instructions) has also split, and will continue to do so until he changes the system. This failure has not discouraged me from prosecuting the enquiry, and I presume it will not deter him. I have for years pursued the study, with the determination to bring it to a successful termination: not by the rule of thumb, but by studying the theory and practice in all their branches.

I have latterly conducted a series of experiments for a considerable time, founded on the plan I considered best suited to us, with great attention to all the circumstances, and accurately registered by instruments, and I must say with very great success I shall refrain at present from saying more on the subject, until I have confirmed my opinions by further trials. Those who have endeavoured to establish the system on scientific principles will be able to appreciate, my motive; for taking longer to prove the truth of my theory; there are such a number of circumstances to be taken into consideration that it takes a long series of trials to place the theory on a sure foundation: and I consider that until the theory is known, the publication of a system, successful in one place might only mislead other parties for want of the knowledge necessary to alter the plan according to circumstances. [scientific rigor in 1843!]

I perceive from what “Perfer et Obdura” states about dunder that he does not understand the reason why the use of it is beneficial; I have never yet met with any work or any person who has been able to give me a rational explanation of the nature and use of it; I do not know that I have as yet been able myself to get over this “pons asinorum”; I have, however, formed an opinion on it, and which opinion seems borne out by facts, but I must give it a longer trial before publishing it. [pons asinorum : literally, asses’ bridge. a critical test of ability or understanding, synonum stumbling block]

In conclusion, I beg to state, that I may not be misunderstood, that no part of what I have written relates to the fermentation of Raw Liquor or cane juice, which is seldom practised, but to the every day management of the still house. I have never had occasion to try fermenting cane juice by O’Keefe’s plan. [Where is this O’Keefe plan!?]

As my opponent states that others are prepared with unquestionable proofs as to the advantages derived from O’Keefe’s plan, in opposition to any parties who may disapprove of his system, I hope that, for the satisfaction of all parties, he will produce them. “Audi alteram partem” ; they will meet with due attention from all planters, and amongst others, -AGRICOLA. [Audi alteram partem : hear the other side too]

P. S.—I see there is another candidate in the field; “in the multitude of counsellors there is wisdom” ; amongst so many Doctors distillation ought soon to become perfect.

February 28, 1843.
[The letter starts to clarify the argument with O’Keefe but we don’t need it all so I’m truncating it]

Sir,—I have read with great pleasure Vallance’s proposal for Sugar Boiling, with your Editorials thereon, as also Churchill’s Essay on the same subject ; the latter is very good, indeed I consider it by far the best article that has yet appeared.

I am not a chemist, and therefore in treating of the subject, I labour under a great disadvantage; yet, notwithstanding, I hope to be able to add something to the general fund of information that may prove useful in bringing our labours to a successful result.

Mr. Vallance proposes to “halve the cost and double the amount of produce,” in the manufacture; that looks well upon paper certainly, especially when you combine with it, that Mr.O’Keefe proposes to double the rum crops, of course also at half the expense; whilst I, as my more peculiar province, promise to halve the cost of cultivating the land, and double the produce per acre.— At this rate we shall soon make sugar estates a profitable speculation. I shall not confine my exertions, however, to the Agricultural department, but shall continue to keep the two other branches; as I have long done, under view with the hopes of improving them. I am now ready to back the old process of fermentation and distillation by the rule of thumb, against the fashionable patent (as it is called) process, and expensive instruments. O’Keefe has not yet equaled, with all the facilities offered him, and with all his exertions and experience, what I accomplished 8 or 10 years ago, as a book-keeper without any assistance or advice. Many other book keepers have also much excelled by the old method his new process. The misfortune was, that they did not know the reason why they succeeded, and therefore could not, under other circumstances, succeed as well. I have, however, I hope, now found out the reasons of the success and failure by the whole process ; and I hereby challenge Mr. O’Keefe to a fair trial of the two methods. If I succeed, shall publish my plan for the benefit of the Island, and show how success may be insured under the different arrangements of the still houses. The arriving at the truth, has been a tedious and troublesome investigation, but I feel quite confident of success. I before time stated that O’Keel’e’s first process (the patent) was wrong in principles; I believe he does not now act at all on that plan; we shall see, if he accepts the challenge, how far he has improved himself by his upwards of twelve months study of the subject with constant and extensive practice. It may be very pleasant to know the use of the instruments, but they are of no real benefit without a perfect knowledge of the art of distillation; they show you that you are not getting the returns you ought to get, and which you know without them; but they do not show where you are wrong or how to rectify the matter. There is only one point in which I believe Mr. O’Keefe and I agree, that is, that every estate should make two puncheons for three hogsheads, without manufacturing any cane-juice into rum; if by furnishing the estates with instruments, and the overseers with the requisite instructions, he has enabled them to make two-thirds of rum, then I shall be satisfied to allow my plan to remain in obscurity. I have made two-thirds in practice, but I have not yet heard that he has succeeded; but, perhaps, some of my St. Thomas in the East friends may inform me on this point of the greatest success that has crowned his efforts in their district. How is it that O’Keefe‘s champion, “Perfer et Obdura,” never took the trouble to answer my former challenge, and to prove the success of what I termed a failure? He put himself forward as the champion, and said if people contradicted O’Keefe’s success, he would prove to the contrary. I flatly contradicted his assertions, and he has never yet produced his proof. This is rather singular in a case of such easy proof! In St. Thos. in the East, on one occasion, I made 83½ puncheons to 134 hogs heads; on another, 31 puncheons to 44 hogsheads; and latterly here, 18 puncheons to 26 hogsheads ; and each time without any cane juice.
[Cane juice in the ferment instead of only molasses I think is the main point of argument. I think eventually it was widely used because it was mentioned by Peter Valaer’s survey of rums in 1937]

March 15, 1843,

I am happy to inform you, that Mr. O’Keefe, has taken up my challenge. The trial is to be, who can make the largest proportion of rum to the sugar made in three months on two large estates; He having the superintendance of, or managing personally, one still house, and I having the superintendance of the other; he is to use some kind of ferment and the instruments, and I am to follow the old plan without yeast or instruments.
[Okay now that we see that O’Keefe has some special instruments and now pitched yeast instead of wild yeast fermentations?]

Mr. Churchill is partly right about the skimmings, although I think he underrates the extraneous matters. When the skimmings are clarified before being used in the still-house, fully two thirds of the quantity is clear cane-juice, and might be boiled into sugar.


April 18, 1843.

What are you gentlemen about, conductors of the press, that mighty engine of weal or woe! guardians of the public interests! Are you slumbering at your posts, so that you know not what is going on in the country? Are you so apathetic that you care not for the interests of the public? Are you under the influence of the mesmeric power, that you cannot act? Or, are you silent from baser motives, that you protect us not, and maintain an imperturbable silence on matters affecting our interests? Ignorance you cannot plead—situated at the centre of attraction, at the very market place of the island, where every body and everything are known—and yet you communicate not the information you obtain.

Eighteen months ago, or thereabouts, a gentleman appeared before the public, proposing to effect improvements on one of the three staple productions of the island, and yet who, from reading your columns, would know whether the scheme had been attended with benefit or injury? Will you allow one-third of the produce of the island to be doubled, or be halved, to be made a foot ball of, and never raise your voices either in commendation or disapprobation of the scheme, and never inform others of the result, to be a warning or an inducement? Shame gentlemen! Planters’ Despatch, send despatches to the Planters, and chronicle the information you possess for their benefit! Journal, Watchman now no longer, watch our interests, and sleep not at your post! Standard does rumour with her thousand tongues never reach thy ears? unfurl the flag of protection, weigh, deliberate, and measure out interests with Standard measure, then fearlessly Gazette the results! let it not be said thou art deficient in moral courage, in energy, or in ability.

The gentleman I have alluded to, (that nothing I say may be considered as alluding to him in his private capacity, but only in his official capacity,) I will call Doctor O.; he will readily be recognised as the party who was to increase enormously the Rum crop. Eighteen months have now elapsed, and it cannot, therefore, be said, that the consideration of his process is prejudging it.

It is a singular parallel in history, that the two great countries of Great Britain and Jamaica should each about the same time stand in need of a physician, and that fortunately in each the Doctor should arise during the crisis to raise the two countries out of their difficulties. Doctor Sir Robert cries out in Great Britain, John Bull is sick and needs a State physician, and I am the man to cure him; call me in and I will prescribe, only my fee first, if you please. Doctor O., a worthy imitator of Doctor R.; re-echoes the cry,—I am the Estate’s physician, call me in and I will fill the proprietors’ pockets with money, only a fee first, if you please. Doctor Peel recommended bleeding, copious bleeding, even to the extent of an Income tax, some say wisely, others not so; Doctor O. also, thinks there is nothing like bleeding, and his first prescription is in every case bleeding. Now, it seems that the patients in both cases, in their distress, and in their joy at the prospect of escape, forgot to make the bargain of “no cure no pay,”and therefore after paying their fee and bleeding freely, find themselves worse than before. It is to prevent such thoughtlessness for the future, that induced the writer to pen these remarks.

Doctor O. having been now so long in practice, having according to his own account had about three hundred Sugar estates under his charge, with fees varying from £20 to .£60, and therefore made a comfortable purse of £10,000; we may surely be allowed, without having improper motives attributed, to see if the country has benefited to a similar amount. As far as I can learn, I say no, decidedly not; it is for you, gentlemen of the press, to ascertain how the truth lies. Some six months ago, the Standard hinted that the success of the plan was doubtful; can you say, gentlemen, that since then you have never received positive information of the result? I have not met with one individual, who, after any length of trial, did not consider it a failure.

In Clarendon, the process of distillation introduced by Doctor O, is, rumour says, totally given up; is this a proof of success?— In Saint Andrew’s, I have not heard the result, but you ought to know. In Saint Thomas in the East, I am.assured by several parties of the highest respectability, that there is not one estate following the plan, but that the’whole of the estates that tried it fell off largely in the returns. It must be remembered that Doctor O. made St. Thomas in the East his residence for months, that he had the finest estates under his charge with unlimited means, and yet the result is as I have stated. To enter more into particulars, one estate, Winchester, I have it from the best authority, paid the Doctor to give up his bargain. Another, Holland, after losing a large quantity of rum, refused to pay him the balance due for his services. At Amity Hall and Hordley, one or both, he did nothing for his money, as he found he was looked after more than was agreeable. To these I may add, Plantain Garden River, Harbour Head, & Retreat Estates, as estates where I knew the process to have been unsuccessful. One gentleman informed me that the returns from the liquor set by the Doctor, after continuing the process for some time, fell off to nothing, as he said (and very properly) that he used sour leaven to excite fermentation, and that the sourness produced sourness until every thing became so sour that maggots were generated in the liquor, and that the people actually would not drink the rum. A party also wrote out from home that the rum was nearly unsaleable. The consequence of all these results was that, one and all, they scrubbed and scoured, and washed, till they got every thing sweet again, and then resumed their old system.
[Don’t forget, all this is pretty much pre-Pasteur so any change to any process comes with great risk of bringing along unfavorable bacteria. O’Keefe apparently tries to pitch yeast that aren’t sound and instead contaminates the ferment with acetobacter]

Such being the case, I remarked that they were very negligent in their duty to their neighbours, by allowing us to be placed in a similar predicament; they said they were so ashamed that nobody liked to come forward; and some even seemed to enjoy the thoughts that they were likely to have partners in their afflictions,—thus verifying the old fable of the fox that lost his tail in a way not very honorable or gratifying to his vanity, and who endeavoured to induce others to adopt his new fashion, which he ventured to suggest was a great improvement. [was everybody in the 19th century this amusing or did this guy stick out like a sore thumb?]

But the Doctor does not confine his assistance to the use of his patent process of fermentation; he also undertakes to instruct in the use of the Instruments—now it will readily suggest itself to the mind of an intelligent reader that the Doctor having failed to instruct himself in the use of the instruments so as to apply them beneficially, is really not a competent person to instruct others in the use of them. For my part, in ninety-nine cases out of a hundred, I consider them perfectly useless, and as soon as the novelty wears off, they will all be laid aside. They have been of use to me in elucidating the science of distillation, but for practical purposes, I shall never use them.

Such being the state of affairs, how is it that the Press maintains an obstinate silence? We, planters, can only attribute it to your not caring for our interests.

I know I shall be found fault with for this publication. Several mutual friends of the Doctor and of me, have already argued with me, if argument it can be called, that I was likely to injure him without benefiting myself; my answer is, if the improvement is no improvement, much more so if it is an, injury, why should all this money change hands; if it is benefiting one party, it is injuring another party to an equivalent amount. It is very disagreeable for any individual to have to find fault publicly with another, but it is a duty due to the public to do so, in a matter of much importance as this; but in a country like this, where the constitution of society is such that all parties are known to each other, these matters ought to be discussed by a disinterested party, the Press.

It is more necessary to notice this matter, as whilst the first scene is enacting, a second scene is in course of preparation, namely the improving the process of sugar boiling. Everybody knows that blood is largely used in refining sugar at home, what, then, such a likely remedy as bleeding, copious bleeding again! Planters, whilst giving every facility in your power, take advice, and let your motto be, “no cure no pay,” and give no certificates of success until after having given the matter a fair and a long trial, bind yourselves to no payment till the benefit is really ascertained.


July 13, 1843.

Sir,—Excuse my addressing you under the above title, as I did not know what other to give you at present. Misfortunes we are all liable to ; you have now got your share; I trust, however, they will not be of long duration,

On behalf of a large portion of the Agricultural interests, I beg to assure you of the admiration in which you are held, for the zeal and talent you have displayed in supporting our interests on all occasions. This feeling will, I am persuaded, induce many besides myself to give you their willing support, whenever the new paper may appear, which I hope will be shortly.

As you have taken a warm interest in the O’Keefe affair, I need scarcely remind you that about four months ago, upon. O’Keefe coming into my district, I challenged him to a trial of skill, at the, same time warning the planters that his improvements had turned out to be a failure, and that at any rate, if determined to try his skill, to take the prudent precaution of not paying him any money in advance. This as might be expected, put him in a thundering rage, he and his satellites abused me in terms not very polite; however, there was no way of escaping the challenge, without palpably convicting himself of imposition.

With a very bad grace indeed he accepted my terms, which were, that I should pursue the old system of distillation for three months on one estate, and that he should put in force his patent system for three months on another estate, the attorney informing us that the average proportion of rum to sugar on the two estates was usually similar, and kindly promising that we should each have fair play.

I have now the gratification of informing you that the result is in favour of the old system.—Mr. O’Keefe, although with constant and most extensive practice for two years, cannot make even a tolerable rum crop, much less instruct other people how to increase theirs.

The public would be surprised at his sly departure from the Island ; the above information will furnish them with a satisfactory reason for the proceeding.

He acknowledged, when accepting the challenge, that if he lost, his hopes would be ruined and it was the consciousness that he would lose, that made him so bitter against me, although I think nothing could be more reasonable than to ask him to give a public demonstration, as he was pocketing such large sums of money, that he really could increase the returns. Accordingly as soon as he finds that the game is up, and that he has no further chance, off he goes without either giving me a parting salute, or bidding those kind friends good-bye, whose cash he has so coolly transferred to his own pocket. Very unkind treatment, very.

I must congratulate those gentlemen living in the leeward parishes who have not yet been honoured with the Doctor’s presence, upon being £50 a piece richer than if he had visited them I assure them Dr. 0. is the most brazen-faced man possible, and possessed of such a mesmeric power that he, in nine cases out of ten, forces the attorney or proprietor to handout £50, and the; Overseer to give him a certificate of success, before he does a thing.

What a last long melancholy look he must have cast to the Westward, when leaving the harbour; perhaps he consoled himself with the idea that the grapes were sour! With very different eyes would he view the estates along the windward coast, as he steamed along.

I would scarcely indulge in these remarks, although I have some right to exult in my success after the shameful way in which he abused me; I say, I would scarcely indulge in these remarks, as I really do not bear him the smallest ill-will, if it were not for the chance that he may be wending his way to some of our fellow colonists to give them a benefit, and if so, the sooner this letter wends its way to the same quarter, the better.

In giving the challenge, it was my intention, if successful, to publish my ideas on distillation; for, mark me, I did not say that I had found out any new system; all that I said was, that everybody knew that very large returns were got by the old plan, but that for some cause or other people could not make sure of obtaining them, and that I thought I had found out the cause why. I propose now to give the result of my experience for the benefit of the public, and let them judge for themselves; if beneficial, they have nothing to pay, and if it should be the means of enabling parties, whose crops have been O’Keefized to make up the losses sustained, then will my victory be complete, and I shall be satisfied.

I shall give my instructions without the use of the instruments; these, before 12 months, will all be laid aside ; people may amuse themselves for a time with them, but they will find that they do not get one wine glass full of rum more than they would have done if they had not used them. [what are these fucking instruments?]

I beg to return my sincere thanks to those parties who voluntarily came forward to support my humble efforts in the public cause, and to encourage me with their approbation, at a time when my opponent was straining every nerve to crush me under his powerful influence.

The still-house under my superintendance, made one and-a-half puncheons over the half during the three months’ trial, although I had to alter several of the arrangements of the still-house at first and which it took, from unavoidable causes, nearly a month to complete; although the alterations themselves did not come to the value of £5. There were also some other causes that operated against me, but which it is unnecessary to specify. All the canes cut during the period too, were rattoons, which reduces the quantity of molasses.
[I think Agricola is claiming he won even though he handicapped himself by cutting rattoons instead of gaining cane but sacrificing future growth.]

The still-house, under the charge of Mr. O’Keeffe has made • • – • •
[The • • – • • is spaced out across the page and taking up a few lines to be the first ever recorded ascii joke. I thought it was funny…]

Having waited until the departure of the Post in the hopes of being able to forward an official return, I must apologise for leaving the last paragraph blank, but hope to be able next post to supply the deficiency.


Postscript, July 19, 1843.

In my last, I was obliged to leave you in suspense, as to the result of O’Keeffe’s process of distillation.

In answer to my repeated applications for information, I have now the pleasure of informing you that the gentleman in charge of the property has determined that “it would be unfair to give me any information concerning Mr. O’Keeffe’s success (qy. failure) in the still-house in his absence, but, that as soon as he returns, every information will be given.” This is tantamount to saying that it is so exceedingly bad, that they are ashamed to confess it; and therefore it is needless for me to say anything further on the subject. When Mr. O’Keeffe comes back, he will, no doubt, of his own accord, publicly acknowledge his failure.



Sir—Strange as it may appear, the great thing in Distillation is the arrangement of the vessels. Under certain arrangements a good crop is almost sure, and under others a bad crop is almost as certain, even after all the exertion that can be used on the part of the bookkeeper ; and this arises from the difficulty of tracing the effect to the cause, as in Distillation there are so many things to be considered, that ten to one, the effect is attributed to the wrong cause.

It is well known that a bookkeeper may make a capital crop on one estate and yet upon removal to another, do what he can, and follow out the same system as much as he is able, he cannot insure the same result. How is this? Some difference occurs in the arrangement, and he thinking, with most people, that every thing depends on the setting of the liquor, is deceived in his expectations. [here when he says liquor he refers to the ferment]

The first essential is to have a mixing cistern capable of holding a vat-and-half of liquor. The mixing cistern is the substitute we employ for yeast ; it acts in the same way.—When a vat of liquor is pumped up, half a vat remaining in a state of strong fermentation impregnates immediately the fresh mixture placed in it, thus insuring a rapid fermentation : this is essential to a good return ; as by a slow process the acetous fermentation goes on simultaneously with the vinous one. [this is about the best they could have done for a starter pre-Pasteur. with this method, most of the time, alcoholic fermentation could out compete acetobacter. At this time the relationship of pH to microbial growth wasn’t completely known, that came later in the early 20th century]

The arrangement of the skimming cistern should be such that the skimmings can be drawn down perfectly clarified every morning, and the cistern be washed out before work recommences in the boiling house; there should be no pump employed for the skimmings as it will always be sour. There should be a dunder cooler, as the dunder employed should always be cold and clarified. [a pump would be too risky on this unfermented material because it could eventually harbor bacteria and fowl the ferment]

The distilling apparatus cannot be altered, but sometimes the method of employing it may be beneficially varied. I consider the still and two retorts the best adapted to our use, and the arrangement generally insures a good return. When only one retort is employed, a very wide difference in the returns may be effected by a very trifling difference in the practice of using it: it is one which would not occur to most people, and was, I must confess, a most complete difficulty to myself for years; and as it will exemplify my argument, I will briefly relate what occurred to myself. [What is being described here is this and it was developed for industrial use in 1801 by Edward Adams, then improved by both Solimani and Berard.]

The Estates I lived on as a Bookkeeper, and where I made good crops, had two retorts, consequently the liquor was put in the still, the weak low-wines into the first retort, and the strong wines into the second retort, and the returns were good. When an Overseer at a different Estate, the rum crop not being good, I took special charge of the still house, and of course expected by following the same plans as when a bookkeeper to obtain the same returns ; I thought at that time, that all depended on the setting of the liquor, and that if the liquor was good, it was no matter by what apparatus distilled, the returns ought to be good also. But no such thing—I could not get good returns: the only difference in the circumstances was that instead of having two, I had only one retort. I argued, however, that that could make no difference; that the liquor to be distilled, whether as liquor or weak low wines or strong wines, was essentially rum and water, and therefore it was no matter how it was distilled. This seems a rational enough argument, and I dare say has occurred to many besides me; it is, however, wrong. Well, I could not get good returns; in fact the more I tried the worse they seemed to get. I argued the point with many of my acquaintances to ascertain the cause of it: two experienced old planters told me, that instead of putting the weak low-wines every day into the still along with the liquor, (for want of having a weak low wine retort,) I ought to keep them till the end of the week, and run a low-wine still. It appeared a very absurd remedy, but it turned out to be correct. I argued with them that whether the spirit and water were distilled in five days, or whether part was kept back and distilled by itself on the sixth day, could make no real difference in the product. They still insisted that it did make such a difference ; they said they could not explain the reason why; but that they had found from experience that such was the case, and in support of their opinions they said that every estate that mixed the low-wines day by day with the liquor did not make a rum crop equal to the half of the sugar crop, and that, on the other hand, every estate that kept the weak low-wines till the end of the week and distilled them separately, made more than the half of rum ; in fact, that all the rum obtained from the low-wine still was a clear increase. I said I could not conceive how such could be the case; but that the facts they stated were very strong and required investigation. [Wow that is a lot. first its pretty amazing that they did so much experimenting and we can see how it all went down in some of the earliest documented days of distillation. What is important to know here is that the low-wines is the product of the first distillation and they are talking about recycling it. Agricola might also be eluding to the size of the hearts fraction. If he distills the low-wines all together where there averaged alcohol content is higher than the averaged alcohol content of the liquor and one portion of low-wines he will get a larger heads fraction. When distilling at a higher proof the congeners are compressed further to the edges of the heads and tales allow you to take a bigger heart fraction. This is explained in one of the Roseworth papers but in a different context. Here the motive is alcohol yield but in other more aroma-centric contexts things change around a little bit.]

I argued the point with many planters, and I considered the subject maturely, but without arriving at the truth; at last I fell in with an intelligent planter (Mr. Espeut) who suggested to me, and for which I think he deserves great credit, the manner in which it occurred, and which immediately carried conviction to my mind. He said he conceived it was because the weak low wines always became slightly acid, and that by putting them into the still with, the liquor, although it could not prejudice the present return, it acted injuriously on the future fermentation by the addition of acid matter to dunder. [Acid here refers to vinegar. here he is talking about mixing low-wines back into the undistilled liquor and because they don’t average above 15.5% alc. which is the acetification point, they risk losing ethanol to acetification]

Now with two retorts the possibility of this injury arising is prevented simply by the different arrangement, and it fully explains how necessary it is to ensure success, that where only one retort is employed the bookkeeper should keep the weak low wines separate from the liquor.

While on this subject it will be well to mention, that the practice adopted by many bookkeepers, of throwing the last two or three cans of low wines, got from the still into the vat of liquor to be run: the next day, instead of into the low wine cask, is equally injurious ; there is always more or less acid in the weak low wines, and the addition of it to the liquor will increase the acidity of the dunder, and re-act on future rounds. [here is where I’m struggling to follow. I suspect he is finding acetic acid in the last fraction he takes, but this acetic acid carries no bacteria (but he doesn’t know that) so he is concerned about recycling it into the ferment. This all makes me suspect they were more concerned with quality than one would think.]


The use of Dunder or Lees has always been a puzzler to parties studying the process of fermentation – in this country, on — comparing it with the system adopted at home. It has always been considered as a useless, if not an injurious ingredient, in the fermenting mixture; the planters have, however, in spite of all opposition adhered steadily to the use of it, and experience, I think, fully proves the correctness of the practice.

Porter, in his work on the Sugar Cane, when treating of Distillation, mentions the general use of Dunder, but thinks it unnecessary, and that the only plea for its use, is, that a part of the sweets of the previous fermentation may sometimes remain in it from the previous process not being properly performed, and that thus, by using the Dunder, the sweets may be returned for re-fermentation and waste be prevented. This is no doubt sometimes the case, but it will not explain the use of it under other circumstances. [Incomplete fermentations might have been common back then. Porter might be George Richardson Porter who wrote The Nature and Properties of the Sugar Cane in 1830]

Dubrunfaut, in his work on Distillation, recommends the use of the Lees on much the same grounds, and on account of economy, by using them warm to prevent the necessity of boiling water for the purpose of heating the fermenting mixture, a very poor reason certainly, and showing that the real nature is not understood.

I have not been able to find a satisfactory explanation of the use of Dunder in any of the works on the subject of tropical Distillation. [what other works were there before 1843 on tropical distillation?]

O’Keeffe started like many others on the English plan, throwing the Dunder overboard as useless; finding, however, his plan a signal failure, he was obliged to return to the use of it, and then endeavoured to account for it, as the addition of an acid, (see the specification of his patent process,) to neutralise the excess of lime, used in Sugar boiling. Taking a leaf out of Dubrunfaut’s French process of fermenting the Molasses from Beet-root Sugar, where the addition of a small quantity of acid is found beneficial, he immediately jumped to the conclusion that such was the use of Dunder, and gave instructions that a certain quantity of cold acid Dunder should be added. Unfortunately for his theory, Dunder happens not to be an acid where the process is properly performed, as l have frequently tested it with limestone and found no effervescence occur. [I had thought plain dunder to be acidic but it might not be as evidenced here. I think in the future when distillers learned about acid catalyzed esterification, sulphuric acid started to be added to the still and that would stay with the dunder because it wasn’t volatile. These writing might be before the era of heavy, high ester rums and this is the beginning of the inquiries that built them.]

Then, what is the use of Dunder? In answering this question I must acknowledge that I do it with some diffidence, knowing that it will be severely criticised by parties conversant with chemistry. I am unfortunately not much versed in chemistry, and must therefore state its use in the light in which it appears to me, and shall be glad if anybody will give a better elucidation of the subject. I think it has a three-fold use.

Its chief use I consider to be in increasing the gravity of the liquor without adding sweet, thereby making the process of fermentation more slow and cool. Liquor set without Dunder works so rapidly that the heat rises to such a point as to cause the spirit as fast as formed to evaporate with the carbonic acid. Liquor set with a sufficient quantity of Dunder works much slower, and ten or fifteen degrees of temperature cooler, and therefore the evaporation of alcohol is avoided. [fermentations they did very slow because of paranoia of losing alcohol might have been beneficial for favorable aroma creation.]

The second use, which was suggested to me by an intelligent friend of mine, the same gentleman I mentioned before, and which I think very probable, is that its use is similar to that of hops in beer; preventing by the bitter principle contained in it the acidification of the sweets employed, and which I think it may be a powerful agent in doing, as the high temperature of the climate and the still higher temperature caused by the natural heating of the fermenting liquor, have a great tendency to cause acidification. Dubrunfaut states that a temperature of from 95 to 100 will cause the fermentation of acid. Liebig states that the less sweet the vegetable juice is, the more liable it is to acidify, and that the juice of Beet-roots fermented at 86 to 95 yields no Alcohol, but a substance called mannite and lactic acid. It seems highly probable therefore that Dunder is useful from the bitter principle contained in it in preventing acidity. [here acidification refers specifically to acetic acid formation]

The third use of Dunder I conceive to be from its accumulating the superfluous yeasty matter or gluten from previous fermentations where there may have been an excess of it employed; and being there ready to be called into play at any time, when from want of skimmings or other causes, there may be a deficiency. Boiling destroys for a time the active power of yeast, but it resumes its power on cooling. Dunder certainly possesses the power of causing fermentation; for on some estates it constantly, and on others occasionally enters into fermentation spontaneously on cooling. This is owing to the liquor having been set too sweet, and a part of the sweet remaining undecomposed, which is always the case where liquor is set too sweet. The gluten accumulated in the Dunder on the cooling of that liquid causes the previously undecomposed sweet to go through the natural process of fermentation. Some book-keepers have a most extraordinary dread of this fermenting dunder, which they call live Dunder, and say that if used, the liquor will never cease working : it is a complete bugbear to them, and they insist on its-being immediately thrown away. It will be seen from the above explanation that it is a perfectly harmless substance, and all that the book-keeper has to do to prevent it, is to set the liquor less sweet for the future. As a book-keeper, my Dunder used constantly to ferment ; at that time I did not know the cause of it, but I never found any injurious results from the use of it as my acquaintances predicted. To show the advantage of knowing even a trifle like this, I may mention for the use of the youngsters now learning the art, that at the end of crop, I filled my vats all half full of Dunder, as usual to keep them water tight, and upon inspecting them, I found they all worked away as if filled with fresh liquor. Oh! said I, “that’s all live dunder, I must throw it away, and I shall have no good Dunder to begin next crop with.” If i had had the knowledge that it was simply a quantity of sweets undecomposed in the previous fermentation, I should have immediately determined to distill it as soon as it ceased working, and I should have accordingly increased the crop two or three puncheons of rum ; on the contrary, for the want of that knowledge, I allowed it to remain unnoticed and uncared for. [this is where is gets interesting and I think the seed for investigating muck and secondary fermentations is planted. they had yeast rich dunder sitting around in vats waiting for the next season and they started to play around with it. they also had tons of alkaline lime laying around because they used it to sanitize vats. eventually they figure out how to produce a little ester generating bio reactor.]

On repeating this circumstance to a friend of mine, he told me of a case in point that occurred to himself. When a bookkeeper, he was ordered to complete a shipment of rum, and not having liquor ready for running, he distilled several vats before the process of fermentation was complete: he found the Dunder from them worked spontaneously ; he pumped it back into the vats ; allowed it to work again, distilled it; and got a good return from it. [these are the mistakes and experiments that start to get repeated systematically]

In distilling all the spirit should be extracted that is possible. Many bookkeepers think it a good plan to leave some spirit in the Dunder to make it strong : if they had said to make it sour, they would have been quite right, the heat of the Dunder after coming out of the still, will cause the spirit left to become almost immediately sour.



Dubrunfaut recommends the clearest spring or well water, as being free from all vegetable and animal matters, and if possible, impregnated with carbonate of lime. There is not much choice for us in this respect; we must use the nearest water ; but sometimes bookkeepers use the tank water, which is generally in a state of partial putrefaction, when they might get cleaner water conveniently from the river. The use of such water injures the return, by causing part of the sweets to undergo the putrefactive fermentation.


The temperature of the fermenting liquid cannot be kept too low. At home, during the height of the operation, they do not allow the temperature to rise above 75, we start at 80 and go up to 95 or upwards. 4

Dubrunfaut recommends one thousand gallon vats to be set at a temperature of 65, and states that they rise about 10 degrees in heat during the fermentation. He states that at 100 the acetous fermentation acts at the expense of the alcohol ; and that besides there is the loss of another quantity of alcohol from evaporation. Liquor set without dunder will frequently work up to 100, besides even at a lower temperature the motion of the liquor is so rapid that the gas in its evolution carries off a considerable portion of alcohol. The addition of a considerable portion of dunder makes, by its gravity, the intestine motion of the liquor slower, and consequently keeps it cooler.


Molasses should not be used in a greater proportion than 10 per cent. The largest proportionate returns I have obtained were from vats set at 8 per cent of molasses, with the usual allowance of skimmings. The proportion of molasses should certainly not exceed 10 per cent, else a part will remain in the dunder undecomposed.

The skimmings are the first cause of fermentation ; if allowed to remain twenty-four hours in the skimming receiver, they will always be found in a state of fermentation. If from any cause there are no skimmings, there is generally a considerable difficulty in exciting fermentation in molasses wash. The skimmings from plant canes ferment much more freely than from rattoons, from containing more natural ferment or gluten in their composition. The skimmings should be drawn down perfectly clarified, as the extraneous vegetable matters favour the destructive or putrefactive fermentation.

When the stillhouse is regularly at Work, the liquor always left in the mixing cistern acts as yeast, and sets the fresh mixture working with rapidity, and without delay. About one half of the mixture maybe of cold clarified dunder. Under these circumstances, the liquor will take about a week to fall, which I consider to be the most favorable period, as that time will allow the fermentation to be sufficiently slow to prevent evaporation, and yet sufficiently rapid to insure the decomposition of all the sweets, and to prevent the acetous fermentation.


The weaker and warmer the liquor is set, the quicker the fermentation will be, and the fermentation may always be made more rapid by the addition of water or warmth.

All the vats should be washed every time they are used, and a quantity of broken limestone, (not quick lime) be kept in each of them, according to a plan long ago recommended by Dr. Higgins in this country, to neutralize acidity as fast as formed; as in the best process some acid will always be formed. [so they were well acquainted by lime and neutralizing acidity which is at the center of managing a muck hole. Dr. Higgins was Bryan Higgins (1741-1818) according to wikipedia “In 1797, Higgins was hired by a public committee in Jamaica for the improvement of the manufacture of Muscovado sugar and rum. He resides in Jamaica from 1797 to 1799. He was some sort of lime master and even held a patent on concrete making.]

Liquor, when nearly finished fermenting, enters very quickly into the acetous fermentation when exposed to the atmosphere, that is to say, the spirits formed follows the natural course of nature, and begins to change into vinegar. To prevent this change, in filling the vat, a space of six or eight inches should be left, and a thin wooden move-able cover should be kept on the vat, not to keep it warm, or to keep in the spirit, as commonly supposed, but to prevent the stratum of gas on the surface of the liquor from being displaced by the breeze; and consequently preventing the partial acidification of the liquor by the atmosphere ; for the carbonic acid gas-evolved during the fermentation being heavier than the atmosphere, lies on the surface of the liquor, and prevents the air having access.

In loading the still, the liquor in the vat should not be turned up, as the sediment will then run into the still, settle at the bottom, become burnt, and injure the flavour of the spirit. When as much liquor has run out from the vat, as will run from the cock, the bottoms should be taken out in pails, or through a plug hole, and thrown into a small vessel to settle, and the clear liquor be afterwards thrown in the next still. If the bottoms are left in the vat, they will become sour, and will taint the new liquor pumped up.

In setting liquor, l have found that by running in all the materials at the same time, such a check was given to the fermentation, that after being well mixed up, the liquor became as it were dead ; upon the recommencement of the fermentation, a thick scum was thrown up in the same manner as liquor yaws in the clarifier ; it should then be skimmed as quickly as possible, by which means a large quantity of dirt is got out of it, and which I could not get by any other process. I have also found that a similar scum was again thrown up on the top of the vat as it was finished pumping, caused in the same way by checking the fermentation ; this must be taken off in the course of a minute, as it seldom lasts longer, the rapid fermentation commencing and carrying the particles up and down. By attending to these two periods, I used to get my liquor beautifully clear.

Regularity is a great thing in distilling. Set a vat of liquor every day, if possible, and always in the same manner, and then, day by day, there will always be a vat ready for distillation ; the regularity will cause an ,economical application of labour, and will save the bookkeeper a great deal of unnecessary annoyance.


And there you have it, the wiley Victorian mind who did a lot for rum making and Jamaican agriculture. I suspect if the interloper, O’Keefe, never came to town, and there was no contest of skill, W.F. Whitehouse would have never meditated on his techniques enough to advance rum distillation. Maybe we can find enough references and clues in the text to fill in the missing pieces to the story and fill in a timeline after this work and before the 1905 works of the Jamaican Agricultural Experiment Station.

Under the nom-de-guerre of “ Agricola,” W. F. Whitehouse published in 1845 various Letters and Essays on Sugar Farming in Jamaica, which he had contributed from time to time to the public press—i. e. “The Royal Gazette and Jamaica Standard,” and “ The Jamaica Times ;”—and 11 few essays written in competition for prizes. In one case, a prize was offered for the best essay on the economic cultivation of the sugar cane for which Agricola competed unsuccessfully. He then proceeded to review the Essays of his competitors including the prize winner, and proved to his own satisfaction that the prize essay was by no means the best. He says, “I am not bold enough to believe but that some of the other essays may be better than my own &c.” ; but he evidently inwardly thought that which he hesitated to state publicly. –Journal of the Institute of Jamaica vol. I (1892)


At Jamaica, in August, W.F. Whitehouse Esq., long and favourably known throughout the island for his devotion to the cause of agricultural science and improvement –Colonial Magazine and East India Review, Volume 9 (1846)

“Muck Hole” Not “Dunder Pit”

[If you enjoy this content, use it professionally, or simply want to support the blog, please share the artisan workshop of the bostonapothecary, the It will hopefully evolve from an architecture focused machine shop to also include a laboratory for distillery analysis and applied yeast work.]

[I’ve done a ton on this topic since and gathered upwards of twenty rare papers on the topic. I’ve been too busy to index anything, but if you search through the posts they can easily be found.]

The previous post contains an account of making Jamaican rum from a 1911 text on Cane Sugar from a renowned sugar technologist at the experiment station of the Hawaiian sugar planters association. The account very briefly explains the various cisterns used for preparing all parts of the sugar wash and uses the (new to me) term muck hole as opposed to the term dunder pit which many rum talkers like to throw around. True, Jamaican rums had dunder added [and this it turns out is ripened with bacterial fermentations], which just implied stillage, but they also had a quotient added called flavour, which is the legendary re-fermented portion. Not all of Jamaica made heavy, flavoured or German rums, they also made clean rums. Many people today are confused on what style of rum is represented by Wray & Nephews OP or Trelawny OP. They are unique relative to other clear rums, but probably do not see any of the flavouring technique.

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

Searching google books for “muck hole”, many great explanations of Jamaican rum production come up as well as one particular old text that is basically the holy grail tell-all of Jamaican rum making at the beginning of the 20th century. I do not not believe this text is known to popular culinary or even the new distilling scene.

Report on the experimental work of the sugar experiment station (1905)

The text is pretty amazing and has staggering amounts of data on experiments conducted. The PDF was scanned poorly and is not searchable, but the content is so historically significant I might be tempted to re-type parts of it over so they are easier to use. Previously, I did not believe there were any works this scholarly being done at this time period concerning rum. It almost seems more advanced than works concerning whiskey or brandy and isn’t listed in any bibliographies that I know of. There is even an appendix of “Lectures on fermentation in relation to Jamaica rum as delivered at the Course for Distillers at the government laboratory in 1906 by Charles Allan, B.Sc.” (PDF p. 284). A likely reason for the advanced nature of the content relative to works of the same time by Scottish researcher S.H. Hastie is that Allan had carte blanche access to whatever he wanted with no legal restrictions unlike Hastie who was severely constrained by the rules of the excise officers.

The text is a compendium of three sections written over three years and at the end of each section rum production is discussed and the author’s handle on the subject gets better and better until finally he pretty much unlocks the secrets of muck hole bacterial fermentations.

Solids from the dunder go into the muck hole. These solids, which are pretty much completely composed of high acid spent lees, undergo a particular bacterial fermentation which produces increased amounts of fatty acids, notably butyric. The muck hole is essentially a pH sensitive bio reactor that is started and stopped constantly by the addition of alkaline lime marl. Besides stalling out with too low a pH, if the muck hole was neglected, the prized fatty acids would continue to break down into simpler molecules like ammonia, but when lime is added and the pH rises, fatty acids are also locked up as salts. Muck can be drawn off or more dunder solids added and the process restarted. Many rum talkers claim the content of the pits could be decades old but I suspect the break down of chemical compounds into undesirable forms like ammonia would not permit this and the contents rather were/are at most only from the previous season’s production.

A wash for a Jamaican rum is composed of sugar cane skimmings, dunder, acid, molasses, and flavour. Deconstructing all these terms is tricky and here is my best shot. Sugar cane skimmings could imply fresh sugar can juice [it is really the raft of coagulated proteins that float to the top with other stuff when you boil cane juice], which was known to be added to Jamaican rums. Dunder here is stillage from a previous distillation similar to backset used in the sour mash process and it often goes through bacterial fermentation as its held during the season. Acid, believe it or not, implies sugar cane vinegar and its role is a clever chemistry trick I’ll discuss next. Molasses is the molasses you’d expect, and flavour, finally, is the muck.

The muck is full of lime marl / fatty acid salts which are essentially locked up in a non-volatile form and needs the acid (again also said as sugar cane vinegar) to unlock. I learned about this concept intimately when creating the Tabasco aromatized gin recipe for my Distiller’s Workbook. The acetic acid in the Tabasco needs to be locked up as a non-volatile salt using baking soda so it does not carry over into the distillate. The chemistry concepts are also masterfully explained in Peter Atkins book Reactions. In the Jamaican rum context, the addition of acetic acid to the muck changes the bonds between the lime marl and a portion of the other fatty acids releasing them to participate in future reactions such as acid catalyzed esterification. So the most common shortest chain fatty acid, acetic, trades places with the longer more noble fatty acids created in the muck hole and become linked up as salts with the lime marl [I think over the years, acetic acid use went away and sulfuric acid became more popular].

The author gives the proportions of sample mashes but doesn’t explain how they are assembled. The muck and sugar cane vinegar could be thrown in with all the other components or left to react independently and then the newly formed lime marl / acetic acids salts separated and the more noble mixture added to the skimmings, molasses, and dunder. The latter option makes the most sense from a chemical perspective.

“Distillery work”, PDF page 471 is also worth a look.

Using google books, five more references were easily findable describing the muck hole and the use of lime. For some reason, none of the PDFs are searchable nor can text be copied and pasted from them. The two 1913 sources and the 1920 seem mostly plagiarized from each other.

The Chemical Age Volume XVIII July-December 1913

The School of mines quarterly A journal of applied science vol. XXXIV 1913

Food Products by Henry Clapp Sherman 1920

British and Foreign Spirits by Charles Tovey 1864

West Indian Bulletin Great Britain Imperial Dept. of Agriculture for the West Indies Vol. VI 1906 (this book looks especially cool!) The manufacture of Jamaican rum is discussed on PDF page 584 and is a summary of Charles Allan’s work in Jamaica which is quite good and fills in some pieces missing in the text from the experiment station. It gets interesting when he starts to paint a broader portrait and gives his opinions of the industry.

Once these imperialist chemists unlocked the secrets of the process, they also uncovered serious inefficiencies. Large amounts of sugar go wasted in each step and some processes were left to run away creating wastes. Spirits production was still very competitive back then and the authors discuss whether it was worth it to cut yields to make a higher ester product at the hopes of making a higher profit. It seems like changing distillery practices incurred more risk and often was just a break even proposition. Advances slowly moved forward over the years probably until we get to Raphael Arroyo’s work on heavy rums patented in 1945 where the techniques used today pretty much get settled.

To quote Arroyo:

It has now been found that heavy rums of excellent type and with high yields and fermentation efficiencies can be obtained by a procedure comprising:
1. The subjection of the raw material to a pre-treating operation which fits it for its intended use.
2. The selection of yeast and bacterial cultures adapted for symbiotic fermentation of heavy rum mashes.
3. The employment of optimum conditions for the production of alcohol and symbiotic fermentation for the production of aroma and flavor, wherewith to obtain high yields and fermentation efficiencies with a rapid fermentation, and a high quality of final product.
4. The employment of a proper distillation method for the resulting beers.

In the Arroyo technique, no dunder or muck hole is used but rather controlled inoculation of selected bacteria in the main ferment coupled with other tightly controlled fermentation variables. Looking at the balance between tradition and innovation it wouldn’t be surprising if for the sake of tradition Jamaica used a modified version of the Arroyo method where the bacterial fermentation was relegated to some sort of tightly controlled cistern / muck hole / dunder pit. One interesting thing to note in Arroyo’s technique is the way he uses alkaline lime during production.

“The addition of the milk of lime during the initial stage of the pre-treatment process has three main purposes:

1. It prepares the medium for the development during fermentation of the most important ingredient in the aroma of heavy rums, being the essential oil or mixture of essential oils known as “rum oil.”

2. It neutralizes the free fatty acids which are always present in molasses, thus eliminating the danger of their volatization during the heating operation which immediately follows, but permitting the reliberation of these fatty acids from their calcium salts upon the sulphuric acid addition to the already cooled thick mash in the second stage of the pretreatment, so that they are then available for the formation of valueable esters later during the fermentation period and under the catalytic action of the esterase produced by the yeast.

3. The disturbance produced in the medium through the alteration of pH value occasioned by the milk of lime causes a copious precipitation of organic bases, molasses gums, and mineral ash constituents of the molasses, and this precipitation is enhanced by the action of the heat applied.

The works of the sugar cane experiment station have been of immense value and it wouldn’t be surprising if other similar works exist for the other islands, particularly those colonized by the English. Maybe there is a text out there that explains the significance and ins & outs of wooden boilers as opposed to copper [I just found this in a Barbados document].

A completing scanning of Raphael Arroyo’s rare text Studies of Rum (spanish) can be found here.

More from the Journal of the Society of the Chemical Industry, volume 26, 1907 which features a very interesting comment section.

The first  named needs no special description. “Skimmings” consist of the scum which rises during the boiling of the cane juice. Before they are allowed to undergo acid fermentation, either alone or in presence of the crushed canes (or “trash”). “Dunder” is the spent wash from the stills.

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