F. I Scard, The Chemistry of Rum

The name F. I. Scard has come up before in a drab paper, Scientific Control of a Rum Distillery. That idea turned out to be slightly more exciting in our recent reframing of Bourbon where we saw that scientific control was something that was significantly aided by onsite excise officers which the West Indies didn’t seem to have in those days. Better control made the collecting of tax revenue much more predictable.

Scard returns with another short paper, The Chemistry of Rum, from 1920. There is some great language in there and some unique factoids.

What might be called the beneficient bacteria of rum, which cause the distinctive flavour, are the acetic acid organism, which produces acetic acid from the alcohol, and the butyric acid organism, which gives from the presence of organic matter peculiar to sugar cane molasses, butyric acid—the same body which gives the characteristic flavour to rancid butter.

We use that rancid butter factoid as common trivia these days, but I’ve never seen it stated that far back.

During distillation the acids mentioned above combine with the alcohol, forming what are known as “esters” or compound ether, and it is these esters which impart the flavour to rum and give it stimulating properties.

I highlight this because Scard mentions stimulating properties. I posited stimulating properties in rum back in my infamous Mezan XO spirits review that ended up with the Mezan XO challenge! Scard was writing before the wide recognition of rum oil as a congener category, to which I attribute the mysterious stimulation rather than esters. Does the logic of his language imply pharmacological stimulation, apart from ethanol, or am I grasping? We have only seen real rum re-enter the market recently so I suggest you drink more to make a better educated decision.

The object of adding sulphuric acid to wash is the produce a certain acidity, thus putting an obstacle in the way of the putrifactive bacteria, which feed on yeast cells, at the same time helping the development of the butyric ferment,  which requires an acid condition for its development. It is the ester formed from this acid which gives the “pineapple” flavour to Jamaica rum. Its presence is essential to all rums, as without this ester the spirit ceases to be rum.

A strong aesthetic pronouncement! Those are rare.

And here we go…

The reason why Jamaica rum contains so much of this body, and is consequentially so valuable, is as follows: The yeast which provides the fermentation in sugar-cane distilleries is derived from the cane itself. The ordinary variety consists of round cellular bodies which grow by budding—that is, one cell buds out from another. This variety, unfortunately, will not flourish when the acidity gets beyond a certain point. When this point is reached—and the production of acetic acid soon brings it about if the fermentation is slow—alcohol production ceases. But in Jamaica there is an especial yeast which will grow in a highly acid medium. Unlike the other yeast, it is rod-shaped, and multiplies by splitting up. The presence of this yeast, therefore, enables the fermentation to be prolonged, and substances such as bottoms, dunder, &c., to be used in the wash, which are favourable to the development of butyric acid.

Here we see the return of our especial hero, Schizosaccharomyces Pombe, which is still not widely recognized in contemporary rum connoisseurship. We don’t exactly know who is using it currently and who isn’t and who was and who stopped. The first person to bring a Pombe rum to the U.S. will have a lot of success. And I’d be happy to help them. There are ways to achieve great ends without a Pombe ferment, but they do not tell such an archaic story of questing Victorian geniuses. They will not be as dank, concentrated, or brick house powerful.

In this connection it may be remarked that the writer on one occasion added butyric ether (ester) to a puncheon of rum in Demerara, which was reported upon in Mincing-lane as “resembling Jamaica”.

There is a lot here besides the admission of fraud. First off, Scard is an island hopper which shows yet again how ideas and know how easily spread between the islands. Everyone was following everyone. Therefore the forces that created style were largely economics, risk tolerance, and responsibility (to process mountains of molasses or not). Mincing-lane was a market for rum and other articles from the West Indies. Lots of tasting descriptors were developed in these markets.

The cane-juice itself is an important factor. Different kinds of canes give a different quality of rum, due, partly, to the case itself and partly to variations in chemical treatment necessitated there in the sugar manufacture. Even the different conditions of the same variety of cane will affect the flavour of the rum. On one occasion some Demerara rum made from very rank Bourbon canes were reported upon as being “green and stalky.” There is therefore outside the ethers specified some bodies present in excessive proportions which come down from the cane itself.

Scard here is arriving at a notion of proto-terroir. He isn’t exactly celebrating variation, but he is noting that variations exist. I’m a little confused by the “rank” canes. These could be moldy rum canes which were prized or be something else. Distilling them could also have been an experiment, and if they were fermented and distilled as a fresh juice rum, they may have had that character on account of not being centrifuged like the fresh juice rhums we know of today.

His closing remarks are nice:

Another agent in flavour is the nature of the still.

Australian Rum Oil and reisling TDN?

[By the end of the post, connections start to be made that I didn’t have a good enough memory to make from the beginning. The existence of this paper was a tip from a particularly smart reader. The punchline may be that components of the mythic rum oil may come from at least two channels. The first is the splitting of glycocides by the enzymatic activity of yeast while the second may be from carotenoids present in the cane itself. Tons of work still needs to be done, but these are some good preliminary guesses of where to look. At the very least, they may point to realizing more terroir in rum, molasses based or otherwise.]

Here is a unique paper, Less Volatile alcohols Esters and Hydrocarbons in a Raw Australian Rum, 1975 (Bundaberg!), which may have a follow up if ILL can track it down. [The follow up is A new approach to the identification of flavour components in rum from the Australian Wine, Brewing, and Spirit Review, 1973. This brief paper was in the bibliography of the other and offers a great summary of what will follow.]

I read this after reading two different modern rum-GCMS papers which were kind of useless for the purpose of learning more about rum history or production. I’ve been aiming to highlight a unique thesis I found with some fantastic explanations of the evolution of chromatography, but I’m short on time and I think I may contact the author first to ask some questions.

In the paper, D.A. Allen reads two early (1966, 1970) rum-GCMS papers and wants to play along, but doesn’t have access to the same equipment. The authors used pentanes to extract congeners from very small samples of rums then analyzed them with GCMS to name volatile components. I’ve actually played with pentane extraction to produce artful creations, but that is another story for another day. Allen could not work with such small samples so he comes up with the novel idea of collecting fusel oil from the side stream of the Bundaberg production then toying with it. Allen’s idea is comparative to that studies that inspired it because most of the unique compounds everyone is looking for are less volatile. The paper ends a little bit abruptly, but he ends up finding the notorius reisling congeners TDN.

I’ll try to describe a little bit of the experiment, but what I should first note with disappointment is that Allen never organoleptically describes anything he is working on. Is he working with that peculiar, wonderful, desired rum oil or is this just low volatility junk? We never really find out here, but maybe we will in his other paper. The whole significance of this paper becomes the old fashioned extraction procedures he uses which may help the contemporary small scale fine producer. Another new possibility is that rum oil congeners may have appreciated in value enough (with our new found fine market) that it is now economically viable to harvest them from a formerly discarded fusel oil fraction. Maybe it is already done for the fragrance industry? Who knows.

Distillery oil, removed in litre quantities from the side of the still was shown to contain these compounds and can be considered as a concentrate of the higher boiling point flavour compounds of rum.


Fractional distillation of distillery oil produced « fusel oil » containing the higher alcohols (n-propanol, isobutanol, isoamyl alcohol and active amyl alcohol, BP to 132°C) and a residue termed « rum » oil containing compounds with a higher boiling point than isoamyl alcohol.  Only the analysis of the « rum » oil will be discussed.

Allen uses both a Lecky and Ewell still and a Bower and Cooke still to purify the fractions for analysis. He has citations for each still and it may be helpful to dig them up to see what they were like. A lot of this equipment is still very useful.

He has got an entire liter of rum oil and does not say how it smells. There are a lot of esters in the oil and they get hydrolyzed with sodium hydroxide to concentrate the remaining compounds. The hydrolysate gets fractionally distilled and the fractions analysed. Part of hydrolysate is alcohols that were liberated from the esters by the sodium hydroxide. Due to how the sample was separated from fusel oil, some compounds like acetals reported in rum oil by others may not have survived.

Allen goes on to perform continuous liquid-liquid extraction on multiple liter batches of raw rum. Its seems like he does five batches and winds up with 5 liters of pentane to distill from. The non volatile product is an oil and the volatile product is split into two fractions. The ethanol was in the first fraction and the second fraction was an oil-water azeotropic mixture. The oil was separated, dried with anhydrous calcium chloride and added to the water-free residue in the pot. It would be nice to know how they smell before he blended them together!

This oil gets redistilled in the same apparatus and separated into two fractions collected up to 132°C so everything is well over the boiling point of water. What isn’t clear is if pentane is used in this distillation. These days this distillation would be done under vacuum and a teflon coated spinning band distillation column would be used because holdup, or the clinging of liquid to the glass apparatus, starts to become significant. Descriptions of what is explicitly happening by now have become a little disjointed and I’m having trouble following the transitions.

This oil was redistilled in the same apparatus and separated into two fractions. The larger fraction, collected up to 132°C, contained the higher alcohols to isoamyl alcohol and was called fusel oil. The residue (100 mL) in the pot contained compounds with higher boiling point than 132°C and was called « rum » oil. After four more such distillations, the combined residue amounted to 500 mL.

If any of this smelled really good, wouldn’t he be likely to mention it? Wouldn’t he be likely to show it to a distiller and get some gears turning? Wouldn’t Bundaberg rum be less likely to be so lame?

In the next step, the specialized stills get some use which apparently feature vacuum and a series of 10mL sample were collected until the temperature hit a certain point. The pressure was dropped and more 10mL samples collected. This multi stage pressure drop to avoid decomposition may have been because the equipment was a little more primitive than what we commonly use today. All of the collected fractions see some spectroscopy to identify what they are.

The rum oil goes through some more hydrolysis with more sodium hydroxide with the products extracted into more pentane.

The paper seems to get cut short after Allen identifies 1,1,6-trimethyl-1,2-dihydronaphthalene. Allen does not use the modern abbreviation of TDN, but this is a congener that is infamous in aged Reislings and is responsible for the petrol character which at the right levels is often prized. Allen drops a little bit of history on this compound but does not mention wine at all. I linked to this paper on TDN in the beginning, but here it is again if anyone wants a primer.

The entire work seems to be the basis of a masters thesis to which the next paper I’ve requested may add to.

I really don’t know what to make of the TDN discovery. Allen does torture his sample and we should remember that in continuous column distillates, this fraction is mostly discarded. Google searches for 1,1,6-trimethyl-1,2-dihydronaphthalene +rum yield nothing.

But, when you read the AWRI paper, TDN is noted as related to carotenoids and extra smart blog reader Matt Power brought them up recently (Matt actually inspired the tracking down of this paper after mentioning 1,1,6-trimethyl-1,2-dihydronaphthalene, but I did not immediately connect the dots):

Are components of rum oils microbiologically derived in these manners, rather than from the canes themselves? Carotenoid bio-decomposition is known to lead to a spectacular array of interesting chemicals

This comment come from the Arroyo’s Oidium post about ethyl tiglate and relates to my hypothesis that the peculiar character of rum oil comes from the splitting of glycosides by the enzymatic action of alt yeasts like Schizosacharomyces Pombe. Rum oil may be more complex and the product of more mechanisms.

Outlining the mechanisms may even unlock the potential for finding more terroir in rum from molasses. A rum can only tell us a story of a place if we learn to read it.

[It may be possible to take a modern GC-MS look at a heavy rum and try to categorize all the low volatility congeners found. This may give us a distribution of what channels they come from.]

Arroyo’s Oidium

In Arroyo’s 1945 Studies on Rum, he presents two different paths for symbiotic fermentations to produce full bodied rums. The first path uses a bacteria while the second path claims to use an Oidium (a mould), but recent research shows it may actually turn out to be a type of alt yeast.

Where did he get the idea anyhow? Arroyo has pretty much no bibliography other than the classic rum texts, but appears to cast a wide net and is well versed in emerging ideas in bio technology. He mentions finding this “mould” on the sap of a tree in a shade grown coffee plantation (shade grown coffee is really interesting). He does not say exactly what specific tree so it is hard to pin down because shade grown coffee plantations are known for spectacular diversity.

Besides, a mould of the Imperfecti group, Oidium Suaveolens, was also found very well adapted for the production of a special type of heavy rum.

Pages later he tell us more:

Another special type of heavy rum was produced during our studies and experiments. This time the raw material used was sugar cane juice. The yeast strain used was No. 764 and the auxiliary ferment was a member of the Fungi Imperfecti, Oidium Suaveolens. The Oidium was found and isolated by the writer from the sap of a tree much used in Puerto Rico for shading coffee plantations.

A study of this Oidium revealed that it would grow very fast in cane sugar juice media with the production of a thick film over the surface of the liquid. It was further discovered that it hardly touched the sugars in the medium, but that it was a good producer of esters and organic acids from the proteins of the raw material. A fragrant odour, very similar to that of ripe apples was the predominant aroma observed.

This Oidium was used as an auxiliary ferment for the production of heavy rums from sugar cane juice in two different ways: (a) a sterilized sugar cane juice mash of from 12.0 to 15.0 per cent total sugars was inoculated firstly with the Oidium culture. After the Oidium film was formed on the surface of the medium it was allowed to act up it for a period that could vary between 24 and 72 hours or more if desired. Then the mash was inoculated with an active footing of yeast No. 764, and the fermentation was carried to completion. (b) In the second method the yeast was allowed to operate alone in the substrate, and towards the finishing of the alcoholic fermentation the Oidium culture was inoculated. The Oidium fermentation was allowed to act then for variable number of hours, as desired.

Both methods worked satisfactorily in the creation of a new variety of heavy rum out of sugar cane juice mashes; but the rums obtained differed somewhat in each case, those produced by method (a) being of intenser taste and higher aromatic tone.

Many databases exist like the Global Biodiversity Information Facility that have listings for the organism, but they contain no spelled out history of discovery that may elude to where Arroyo got the idea (A Russian database points us to Geotrichum Frangrans which can be purchased here from the American Type Culture Collection ATCC). Arroyo did name the organism correctly as Suaveolens, and calling it an Oidium may point to the Russian biologist Krzemecki who possibly discovered it in 1913 based on language included in the GBIF entry. Arroyo may have also been hip to the organism by reading the mycologist Christine Marie Berkhout. Or maybe Arroyo never read her 1923 doctoral thesis that (quoting wikipedia) was later described as marking “the beginning of the rational systematics of the anascosporogenous yeasts” (I’m way out of my depth, but trying to bridge the gap between Arroyo’s mould and the recent researcher’s recategorization as yeast. The difference between a mold and a yeast is that molds grow with multi celled hyphae while yeast’s are single celled).

We are building up to some links to great modern research papers, but we should pause for a moment. The whole point of this exercise is to (a) celebrate how fucking cool Arroyo was, (b) help modern rum writers who may talk to producers and find evidence of these techniques used in a production, (c) help new producers jump off on this, and lastly (d) celebrate the contemporary researchers who will help us bring more of Arroyo back to life and create new exciting styles of rum.

Contemporary research on this organism and my realization that Arroyo may have been incorrect about it being an Oidium are lead by Thomas Petit and Eric Grondin working on the island of Reunion off the coast of Madagascar.

This brief info graphic style paper by Petit mentions participation in a European COST (cooperation in science & technology) bioflavour project. After scouting yeasts, Suaveolens, came up as their most significant flavor producer, specifically producing the valuable ester, ethyl tiglate (a known semio-chemical #pheramone).

To back track a bit, from an old text that summarizes abstracts, we can glean a little bit of the interest from 1923.

A study of Ester-Forming Yeasts.
Ulrich Weber, Biochem. Ztshr., Berlin 129:208, April 19, 1922.
Experiments are described that sought to determine the conditions under which the formation of fragrant esters takes place in some lower fungi. The question was dealt with by physiologic experimental methods. There were employed Willia saturnus Klöcker, Oïdium suaveolens Krzemecki and Siachsia suaveolens Linder. These organisms were raised in pure cultures in nutrient glycerin and mannite solutions under different conditions.

Results showed: In the observed yeasts and imperfecti fungi the ester odor typical for normal cases is not developed under all conditions. Cases occur in which, in spite of the most abundant development, no ester formation takes place, as in the case of growth in a carbon dioxide atmosphere. Esters are formed only when the simultaneous fermentation of carbohydrates assumes the role of sugar fermentation and liberates the energy requisite for the decomposition of albumin. Addition of alcohol enables a qualitative alteration of the ester odor to be attained. The employment of different nitrogenous nutrient media achieves an alteration of the odor only when other amino-acids are thereby presented simultaneously. Following addition of leucin a distinct odor of amylester is perceived. The ester odor of the species here investigated, which is always observable under normal conditions, is therefore capable of being influenced experimentally both qualitatively and quantitatively, as it is possible to alter both the character of the odor and also to prevent its occurrence in spite of the best development of the fungus.

The Yeast, A Taxonomic Study has some useful information on understanding what exactly the Saprochaete of Saprochaete Suaveolens entails.

Swedish Wikipedia provides a great bibliography.

And finally we come to a few spectacular modern research papers:

2016 Retrospective

Being December, it is time for the year end retrospective. Like usual, I felt like I didn’t accomplish much, but I did write about 20 posts with some containing distilled spirits’ most significant historic discoveries for the year (examining Arroyo) and others containing distilled spirits’ most progressive ideas (congeners derived from glycosides).

I have put a lot of beverage work on hold to become a design world darling and start the Houghton Street Foundry (IG: @houghtonstfoundry) which makes exquisite door hardware and offers architectural machining services. I have ghost written a few products for small distilleries with one being the hottest off premise specialty product in New England, though I actually think I designed it last calendar year. My beverage pace has slowed down, but I’m still holding significant technique and history secrets from the industry (to punish you all!).

The year started with Rum Comparatively: Understanding Anything Goes and explains how production compares to other spirits categories and why rum is the most progressive spirit with unique production templates that other categories do not use.

Aggressive collecting led me to Excise Anecdotes from Arrack Country which tells some of the most breath taking (and heart breaking) distilling stories ever recorded. It also ends with a beautiful discovery and meditation on terroir.

There is a ton of WTF? in Rum, Mitogenic Radiation & The Bio-photon. Brilliant Science writer, Adam Rogers, was cool enough to spend time weighing in so I had a lot of fun with the post. It does show that Rafael Arroyo was a far out thinker with an ear to the ground and yet again reinforces the idea of rum as the most progressive spirit. Nearly a century of science later not much is clarified.

This was particularly important to me because I’ve long been a champion of the rums of Cape Verde. In Cape Verde and Sugar Cane Juice Rum Categories I apply explanations from Arroyo to my favorite distilling tradition and explain the origins of their distinct aromas. There are so many supposed rum experts and they are still avoiding Cape Verde and the island of Madeira. Berry’s or Plantations rums, where you at? I’ll connect you to Cape Verde’s most brilliant distillery.

Here I describe my plan for discovering a new generation of champion rum yeasts: Team Pombe and the Yeast Olympiad. So far I haven’t been able to get it off the ground because of a lack of interest from the small distilleries in my circle (and the very expensive process). I will likely finance and execute the ideas by myself and I’m not afraid if it takes quick a few years. No one else seems to be too interested in this territory.

Rum, Osmotolerance and the Lash was so much more than a cute title and looks at forces that shape microbial communities, especially when trying to cultivate a dominant Pombe fermentation.

I had heard murmers of these ideas so long ago from Ed Hamilton so I decided to tackle them in Aroma Breakage and Rum Design. Arroyo as usual was on top of everything. Some new producers like Maggie Campbell of Privateer are known to be very much hip to this and weave the ideas in production.

Ageing, Accelerated Ageing, & Élevage ==> Lies, Damn Lies & Statistics This was my look at Arroyo’s progressive musing on the aging topic. I think this was before I read UC Davis great, Vernon Singleton’s, legendary paper which I probably should have given its own post (2017!)

Narrative of the 1975 Rum Symposium

Say it with me:
Rum is the most progressive spirits category.
Rum has the most researched spirits production.
There is nothing finer than rum as we make it.

There is so much good stuff in the symposium.

I had never done a spirits review before and of course I did it on my own terms. This post, Spirits Review: Mezan XO Jamaica Rum, also ends up with a challenge of drinking 10 ounces in one sitting to test a theory many are anecdotally validating. I also drop one of the most progressive ideas in all distilling and introduce a new congener category. Its not my fault if people cannot keep up.


Before I left to run a popup in Province Town this summer, I introduced For Sale: Large Bottle Bottler. This tool is particularly awesome but not for everyone and I don’t push it. Some bars are killing it with my bottlers and I am in some of the world’s top programs while other notable programs cannot assemble a team that can handle the tasks. A lot of a sales go to winemakers doing research projects for their own product development. I owe you all a new post on kegging to show you’ve all been doing it so so wrong.

In the frustration of the election and inspired by blog hero George Lakoff, I penned Public foundations for Private Spirits Companies. The post is a meditation on how private companies get built on a foundation of public research and how we are starting to forget that. A new generation of distilleries is popping up that often flounders with the technical aspects of product development because they do not seek out any of the amazing research that came before them. Most distillers are in disbelief the research exists when I introduce it to them. This rickety blog is the largest source of advanced educational material for the new American distilling industry which is approaching a billion dollars in revenue and quite a few hundred million in investment.


Here I introduce the Alaska Ice Crusher and describe a stunning restored version produced by a new friend. I’ve used Alaskas for a quite a few years and lately have been seeing them popping up in finer bars. They have become a Boston bar scene thing and collectively we own quite a few.

In A Few Papers For The Industrious I take a break from foundry work to read from papers that Rex sent in which I’d been hoping to come across for a few years now. Having gotten in the mood, I also shared up some delicious snippets from the archives of rum arcana.

Patrick Neilson Tells of Rum (Like No Other), 1871 This was easily my favorite piece of the entire years with its companion article J.S. Tells of Rum, Jamaica 1871. These papers kick off the fine rum era and are full of the choicest opinions on things like skimmings that many of us have heard of but don’t quite understand.

This piece was short and fun and simply shows that even as far back as 1885, which is a few life times out from the birth of the term, people were into tracking down etymologies: Etymology of the Word Rum by Darnell Davis (1885).

This is only for nerds and if you’re short on time and need to triage your reading, skip this, Occurance of Lime-Incrustations in Rum Stills (1903), and the next post, Scientific Control of a Rum Distillery by F. I. Scard.

As I collect papers, a genre of writings is emerging and this is an enjoyable example from a seldom described island. W. M. Miller Tells of Rum in Guyana for Timehri (1890)


We ended the year with the Return of the Champagne Bottle Manifold where I mastered single point threading on the manual engine lathe and started cutting the proprietary 19/32-18 threads myself to improve the design. My design over the years has evolved to be really spectacular, but they didn’t really catch on because programs didn’t want to pay for them and those that did had them frequently stolen. The most serious users ended up being Champagne sales reps.

Who knows what next year will bring. Sadly for the Bostonapothecary blog, my focus will be in the workshop. Ask questions or challenge me and I may sit down and post.


W. M. Miller Tells of Rum in Guyana for Timehri (1890)

In Guyana, rum had attracted yet another Victorian genius and that was W.M. Miller. His article for the amazing publication Timehri reinforces the idea that rum consistently attracted PhD level scientists to push it ever progressively forward.

This article is pretty cool and after reading so many of these I keep coming across little subtleties that show the evolution of ideas. Thinkers like Micko or Arroyo did not come out of nowhere, but rather came from a continuous line of thinkers at the forefront who were happy to share their ideas. Greatness in distillation is not about secrets, it is about execution.

In reports on estate’s work it may have a few lines devoted to it; but it is seldom that any genuine interest is taken in it, either in its manufacture or in its quality. The usual feeling is that the rum makes itself, and does not require any looking after. The molasses is diluted and the wash distilled; and if the results are low, the molasses is blamed; and if the rum is bad, the distiller gets a reminder.

Wine making itself is an adage & rhetoric of the terroir scene, but it is far from the truth. To bridge the gap, I try to differentiate between traditional processes and guided traditional processes.

But in these latter days there has been a brightening up of interest about rum. The Government meditate new legislation; and home buyers are becoming more fastidious owing to the quantities of continental root spirit, called “Rum,” that are thrown on the English market. This latter reason soon affects the manager of the estate, and for some time there is continuous rubbing of hands and sniffing, with more or less satisfaction—generally less.

Beautiful language and we see that old technique—rub a little spirit into the hands to open it it up, then sniff! The continental spirit is made from sugar beets and supposedly, though a lot of effort has been thrown at them, they just can’t make a product with aroma worthy of being called rum.

We have the misfortune to cater to a fancy of the most changeable type. So it is with rum. We have to suit an unknown personal taste, and, let us do our best, if we halve a sample, A. will laud it, while B. will probably call it “beastly stuff.” But the chances are that B. does not know what a good rum is, as the sniffing test is still fashionable; and we come back again to the desirability of a “polariscope,” wherein B’s taste is the optical part that indicates “beastly stuff.” In others words, if we had such ready chemical tests as could permanently record B’s taste in some fixed way, we should be able to avoid shocking B., and at the same time to please A.

A segmented market was on his mind. The polariscope idea is basically to turn a rum into a definite number. Even now with GC-MS we don’t know exactly what chemical compounds correlate with notions of quality. Personally, I love wandering in the realm of acquired tastes.

It is with the hope, therefore, that some universal method may be introduced, not only here but by the buyers also, so that every one’s particular liking may be recorded in figures, that I have come forward with the following contribution to the subject. The “everybody” in this case is probably a few individuals in two or three markets.

This became a bit of a quest for a lot of people, and I do enjoy the way Arroyo avoided it. We always need to remember that the occasion around a sensory experience adds rhetorical power and shapes taste while so does context and telling the story of a fine spirit. Taste, especially when cultivation becomes a hobby is especially malleable. We are no longer authentic hard laborers drinking the same product on end simply to quench our thirst and sooth our sores.

Another reason that should demand the more systematic analysis of rum is the desire to guard our product from being imitated by the Continental spirit. Unless analyses of the genuine spirit be well known and widely circulated, analysts would find some difficulty in distinguishing the genuine from the imitation.

These aspirations become very significant and the efforts also produced much better genuine rum.

The usual here is to allow the fermentation to proceed spontaneously, and if a return of 5 percent, to 6 percent, of 40 O.P. spirit be obtained from the wash set at 1o6o the result considered satisfactory.

Simply we note they were still practicing spontaneous fermentations, but we should think of these very differently than wine.

In practice, as before stated, it is usual to allow the fermentation to proceed spontaneously. The addition of sulphuric acid or ammonia sulphate does not in the least start the fermentation. They may, or may not, improve the wash and make it a more suitable medium for the development of the yeast, but unless yeast in some way gets added, the addition of any quantity of these bodies can be of no use in starting fermentation. During grinding operations little trouble is found in starting fermentation through the addition, one way or the other, of the highly fermentable washings and scums; but if distillation has to be conducted by itself, after a period of rest, the trouble in starting a good fermentation and the low results, will no doubt be remembered by any one who has had to deal with it. To find the reason of this we must consider what fermentation is.

Here is some juicy morsels. There was often trouble starting fermentations later in the season when skimmings were no longer available. It was not yet realized how to create a starter and how stages of yeast reproduction differed from stages of alcoholic fermentation.

But what is in the scums and skimming!? This is the cream if you remember. Are they particularly rich in the building blocks of yeast growth? and/or valueable aroma precursors like glycosides? Who knows and these fractions might not even exist anymore due to large advances in sugar processing. What is their official status?

Alcoholic fermentation is the change a saccharine solution undergoes when the yeast plant developes in it. Being a plant, yeast wants food very much the same as other plants, and unless the foods are there it will not develope. But every variety of plant has one special soil best suited to it ; and if it is our object to cultivate any particular plant, it is to our advantage to give it the food on which it flourishes best. Yeast requires carbohydrates such as glucose, mineral matter in the form of potassium phosphate with a little of the phosphates of lime and magnesia, and albumenoid bodies which must be in the soluble state. The reason why these foods must be in the soluble state, is that the yeast only feeds, as it were, through its skin.

Great metaphors. Arroyo had really great explanations of how fermentations get stuck.

In molasses, we have the carbohydrates and probably sufficient alkaline phosphates, but the soluble albumenoids are altogether wanting. It is owing to their absence that fermentation is not readily started in molasses. In cane juice, on the other hand, these albumenoids are in the best assimilable state, and hence the rapid fermentation that is so easily set up. We have here a very easy means then of establishing fermentation in molasses.

Here we go. I also suspect that the yeast count on the skins of canes or grapes or fruit, or anything not boiled like molasses is very significant and helps it burst into rapid fermentation.

A little “cush-cush” can be made at a moment’s notice, which, when once fermented, will serve to start the vat. The yeast when once started has the power to render soluble the insoluble albumenoids that exist in the molasses, so that the fermentation will then proceed of itself.

He drops the cush-cush! His explanation here may be spurious.

The advantage of establishing a vigorous and healthy fermentation cannot be too strongly recommended. It alone produces a pure alcohol. The languid insipid vat is productive of fusel oil, besides becoming an easy prey to the action of deleterious ferments.

Arroyo eventually takes the math of the starter to the nth degree and explains how to figure out how big exactly they should be and what is compromised when size changes.

The only means of escape then is to start such a vigorous fermentation that the predominance of the yeast will entirely obscure the harm done by the other ferments or kill them to a great extent; for in fermentation, as well as in everything else, it is only that which is adapted to the environment that flourishes.

Sage advice. There is the phenomenon of killer yeasts, but I’m not sure if that is what Miller is intuiting here.

As it is in the beginning of the fermentation that the lactic acid ferment is likely to get a hold, the necessity for quick starting of the alcoholic fermentation is obvious. Towards the end both the alcohol and the acid developed keeps it in check, but neither of these (the alcohol and acid) restrain much the action of the acetic acid ferment which begins to be very evident towards the end of the alcoholic fermentation. The appearance of a peculiar film on the surface of the wash indicates the presence of a species of Saccharomyces that is busy changing the spirit into acetic acid. It should be beaten down under the surface where it cannot obtain the oxygen necessary to destroy the spirit.

Interesting stuff in here. A lot of different things can grow in rum ferments and Miller probably knows a vinegar mother when he sees one (or smells one). I wouldn’t have thought it would be effective to punch it down below the surface. I’d have thought it would either float back up or be encouraged by whipping oxygen into the brew, but Miller seems like he achieves success. Was it common to witness all sorts of deleterious growths and deal with them as such? There are top fermenting saccharomyces yeasts, but this seems different. There are also weird mucusy growths that can turn a ferment into thick scum. When you’ve got them you’re on your way to a kombucha SCOBY.

This is not the Acetic Acid ferment proper. It develops throughout the whole wash and is quite a different organism. It flourishes best at the same temperature as yeast and is thus difficult to restrain,but as it only appears after the alcohol is formed, much damage by it may be avoided by distillation at once.

For me, this isn’t ringing a bell yet.

The butyric acid ferment feeds on the fatty matters present. It is to the acid that this ferment produces, in combination with the alcohol, that the flavour of rum is partly due. The distillation of the wash should be conducted as regularly as possible. Any rapid increase in the temperature forces over impurities that otherwise should be retained by the rectifier. The temperature at the exit of the rectifier should not exceed 18o deg, F.

The big reason pot still distillation needs to be slow and regular is that a more rapid boil challenges the subtle reflux contributed by the walls of the still. Reducing this subtle often over looked reflux drops the distillation proof and allows more congeners to come across in the hearts fraction. The spirit exiting should be kept cool so that it does not evaporate creating a loss and so as that it doesn’t dissolve the copper of the still. Inadequate condensing temp is a big problem for the bush rums of the world in places like Trinidad and Cape Verde.

I’ll skip Miller’s explanation of all the congener classes which is actually notably cool. He is wrong sometimes but shows how much they knew and how much they were willing to take a stab at back then. Brilliant.

Measure out 25 c.c. of the alcohol into a small glass flask, and drop in 15 c.c. strong sulphuric acid. Pure alcohol when treated in this way gives no colouration, but the presence of aldehyde gives the solution a brown colour, and the fusel oil a dark purple.

Arroyo practiced this test not to measure congeners by coloration like Miller but to chemically reveal rum oil. Other aromas are rendered neutral by reaction with the strong acid.

Tested in this way, the ” heads” of a still give very deep dark browns, which fall very quickly and give place to a pink with a trace of blue; which continues till about the time when the “low wines is cut,” when there is a sudden rise of colour, the dull purple predominating. The white rum itself can be tested in this way, and fair comparative results obtained.

Fascinating. I’ve been itching to do this test and was promised some surplus acid. I already hatching a plan for what can artfully be done with it.

The testing of rums which are already coloured, with sulphuric, of course cannot be done. It becomes first necessary to distill it from the colours. This should be done rapidly without the addition of any alkali, till all has passed over that can, without burning, the first-third and second-third being caught separate from the last. Halve each of the thirds, and mix them, this will represent the rum; and test the other portions separately. These separate portions will give further insight into the nature of the rum.

Very profound if you look at the ideas of Micko and Arroyo that come later. Let me quote it again:

These separate portions will give further insight into the nature of the rum.

This idea elaborated is everything.


Scientific Control of a Rum Distillery by F. I. Scard

This great (possibly 19-teens?) article from the International Sugar Journal by F. I. Scard immediately brings up some themes I’ve been talking about in distillation. For starters, Scard was a name who criticized the Veley’s in their debacle over the micro organism of faulty rum 91898). Remember the punchline?—the organism might simply have been decomposed raw meat! And the hint comes from a comment by IRS researcher extraordinaire, Peter Valaer in 1937. Can you not see this wicked web we’re weaving?

Any how, the idea I’m promoting is that just like fine wine did not exist without the lab, the same is true for spirits. The winners of the judgement of Paris were all lab guys and the same will be true for great distillers past and future, skipping the present.

In the case of a rum distillery the position is very different. It is not the sucrose alone which has to be accounted for in the course of manufacture, but all the formentable sugars, glucose, and invert sugar, as well as sucrose, which find their way to the distillery. The object of the operations of a distillery is not to separate and obtain these sugars as such, but as a product formed from them by biological means before its actual separation by distillation, a product in which the flavour is a vital point in its value. The microscope thus plays an important part in the control of a distillery.

Here we have language that sums up chemical and biological control and shows conscientiousness. The science goes on to get very heavy and shows that people of PhD level science education were involved in the production of fine rums. After much heavy duty science wanking Scard puts a time stamp on a known technique for making fine rums:

It sometimes happens that the wash is not sot up all at once, but that fermentation is allowed, purposely, to start before the set is completed, being gradually fed with “sweets” until the desired charge is obtained. In this case the constituents of the wash must be measured separately, and the sweets determined separately too.

Incremental feeding of washes was a technique further elaborated years later by Arroyo and may be unique to rum fermentations. He does later go on to criticize the technique possibly because it does not fit neatly into his idea of control.

As already mentioned, the microscope plays an important part in the control of the fermenting loft. The great enemy to fermentation is the putrefactive, bacillus and the wash requires to be constantly examined for the presence of these organism. A few are invariably present, but, if the condition of the wash is favourable to their development, the yeast plant is soon smothered, and there is nothing else to be done but to clean up the distillery in every detail. It is as well also to keep a microscopic eye on the yeast plant, to see if it is developing properly, and at the same time to look out for moulds or other organisms inimical to the yield of alcohol.

Oh, maybe we are not talking about fine rum here after all, but rather the commodity category? Fine products require a certain philosophy where control isn’t sought completely, but rather just enough control to frame windows for chaos. Arroyo later showed us the benefits of controlled putrefactive fermentation and aroma beneficial moulds. The rums of Hampden estates go on to tell a very singular story where they break all the rules and there is certainly no one going around “cleaning up the distillery in every detail.”

The number of gallons going to the still in the form of wash during the week is recorded, together with the amount of alcohol received from it. These should agree within 5 per cent, with a pot still and 1 per cent, with a continuous still. The lees, or spent wash, should also be examined for alcohol by distillation, daily in the case of a continuous still, and from every distillation with a pot still, to see if any alcohol is escaping in this way. 250 c.c. should be taken and 50 c.c. distilled off, the gravity of which is taken with a specific gravity bottle, and corrected for temperature, when any loss of alcohol will be at once discovered.

This test can be run with a profit motive, but if you put in the time, you’ll also learn about lost aroma. With a flipped motive, fine rums can benefit from many of the same protocols as commodity rums.

In order to ascertain the amount of spirit obscured, the following is a reliable and simple method, and preferable to the distillation method in the case of strong spirits like rum. The specific gravity of the coloured spirit is taken in a specific gravity bottle, or by Sikes’ tables, if the Sikes’ hydrometer is used. 100 c.c. are then taken and evaporated until all the spirit has been driven off, i.e., when the residue has reached a syrupy consistency. The residue is now dissolved in water, and made up accurately to 100 c.c. at the same temperature at which the gravity of the coloured spirit was obtained. The specific gravity is now taken. The decimal part of the gravity is then subtracted from the gravity of the coloured spirit, the remainder giving tho gravity of the spirit without the colour. From this gravity the quantity of alcohol present can be obtained by reference to tables.

Currently the TTB requires the distillation version of the test, but the version presented by Scard (and arrived at my myself independently years ago for studying liqueurs) is remarkably easy and with modern day instruments can be performed on remarkably small scales with amazing accuracy. Small, 5mL, volumes of historic rums could be sacrificed to get this data. There is huge criticism of obscuration in the rum world and yet no leading authority has been sophisticated enough to perform this test for themselves. From 5mL-10mL samples, and a collection of bottles, it would take very little from the rum community to look at the obscuration changes in many brands over recent history. If consumers feel obscuration is important to the fine rum category then here you go.

Faults in rum are found by the following test. A portion of the coloured rum taken from the cask before shipment is diluted with twice its volume of distilled water if it is strong rum of the Demorara description, or with an equal volume if of the weaker Jamaica kind. It is then placed in a small cylinder covered over with a glass plate, and allowed to stand for 24 hours. If at the end of this period there is no appearance of cloudiness the rum is free from “faults.” If a cloudiness appears it may be due to :—
(1) Resinous matter from the wood of the cask ;
(2) A precipitate from too-highly burnt colour ;
(8) The presence of low bodies of the fusel oil class which should have been kept back in the low wines.

Other reasons have popped up for faulty rum and I put up a great series of papers the other day.


Occurance of Lime-Incrustations in Rum Stills (1903)

This is a short fun one from the 1903 International Sugar Journal. Many of us think of old school rum washes as being quite dirty, but what toll did it take on equipment? And what does it tell us about Arroyo’s focus a few decades later?

By 1903 sulphuric acid was in wide spread use to acidity fermentations and that led to lots of salt deposits.

So all of the biggest concerns were from commodity rums produced on continuous column stills and not the fine rums produced on pot stills where they could simply discharge and then flush out.

This phenomenon where alcohol changes how the crystals form may be why I’ve had much better success creating sugar cubes in an alcohol/water solution than in water alone (a project from probably six years ago). Very interesting.

What he goes on to explain is that sugar and acidity in the wash increase the solubility of gypsum so that 1 part to 400 part drops considerably. Gypsum actually precipitates as the wash ferments because the sugar content decreases.

These ideas are before the era of the Alfa Laval continuous centrifuge.

It would be Arroyo’s focus to go on and solve a lot of these problems with new ideas in molasses pre-treatment which resulted in significant advances to commodity rum production. It is hard to say if Arroyo faced the exact same challenges. As sugar producers gained increased chemical control and gathered more data, they were able to produce higher quality molasses. A lot of what Arroyo removed from molasses was not exactly gypsum but gums and other materials that could impede fermentation besides clogging a continuous still.

Etymology of the Word Rum by Darnell Davis (1885)

A fun snippet from the files is this 1885 look at the etymology of the word rum. Judging by titles of his other works, the author, the honorable Darnell Davis, was quite the character, but so far I haven’t figured out if he was any kind of colonialist racist or not. Google has no full view of his essays, but I’ve yet to consult other resources (too busy at the foundry).

Davis’ work comes a whole 200 years after the birth of the word, rum, at a time that was pretty much the birth of modern rum with any stylistic identity (beginning of chemical and then later biological control).

Most enthusiasts today believe there are few works on the subject, but rum it turns out, has the most well documented history of any spirit category. This blog has become sort of a monument to and repository of that technical history.

Categorizing rum is all the rage, and lately in discussions, I’ve been promoting the top most categories of fine rum and commodity rum (which we will eventually sub categorize). This backs away from cliches like sipping and mixing as well as industrial and artisan. It is no revolution in rum categorization, but the words are semantically powerful and have been very valuable to understanding wine. Wine, we will repeatedly see, is where we should look when figuring out how to categorize and market rum.

My big point is that fine rums exist, and they are certainly out there on the market, but the category does not yet exist. We cannot have fine rums sorted from all the commodity junk until the complete history of rum comes out. We just went from thinking Jamaican rum was shrouded in mystery to finding out it has the most documented history of any spirit complete with time stamps, intimate anecdotes, and first names galore.

Fine wines tell a story, and that is largely their whole point, but we cannot read it unless we clearly know how they were produced. Things we don’t quite understand like the contribution of cane varieties cannot be pulled apart until the other variable are isolated by disclosure. We still have no wide acknowledgement of Schizosaccharomyces Pombe as a rum yeast. Giant holes exist in rum knowledge that would change any categorization system so I think a lot of people are getting ahead of themselves.

Fine rums cannot tell their story until we know more about them starting with their technical history and evolution. This has nothing to do with banishing caramel coloring or the arbitrary numbers attached to a solera system. Dwelling there will just set rum back. The future of fine rum literature will probably resemble Andrew Jefford’s writing on wine, but it is nowhere near there at the moment.

Darnell Davis’ 1885 etymology of rum is another step in telling the history of rum that will get us closer to the category of fine rum. Pulling these papers out is less about helping to produce better rum (like some of my efforts for new distillers) and more about helping to read rum. We need a continuous story from the birth of the word to the bottles we are currently enjoying.

Spirits get shaped by countless influences from the cultural to the philosophical to the scientific. Wars shape spirits and so do unique government programs like the various experiment stations or the infamous Rum Pilot Plant. The fine category begins with chemical and biological control to sculpt a spirit into an ideal and then the philosophical is free to take over.

Fine wine, we must remember, was born in the lab. The American winners of the Judgement of Paris were all lab technicians turned winemakers. This allowed them to follow the progressive process of incremental improvement for their wine. These producers, particularly Warren Winiarski, were deeply involved in the philosophical end of wine construction, but they also had the technical foundation to execute all their ideas.

Let’s quote Winiarski because it is wildly relevant:

That was also there. All of those things. We didn’t talk about the major ingredient, the accumulation of scientific information and things that people did at Davis. Maynard Amerine’s work with grapes and where they grow best –that bulletin of the Agriculture Experiment Station at the University of California that I used as a Bible, reading it in a devotional way. Every day you read a little bit of this, at night you read a little bit of that, getting intimately immersed in the contents. You read another chapter and tried to figure out what these must analyses could mean and what their significance was. The existence of such a rich body of knowledge was certainly another major ingredient. And I think the other thing was the people, among whom I count myself, whose taste and aspirations were formed elsewhere and who brought in the ability to actually accomplish the coming together of these several elements.

Maynard Amerine and the culture of that UC Davis era have always been a guide for the work at the Bostonapothecary. A Winiarski or a Grgich of the rum world will not come along until we assemble and digest all the literature. Also, notice that Winiarski et al. were studying texts meant for commodity wine production. These fine wine makers literally sat in (old school non degree sat in) the back of the class to learn anything that might help them produce fine wines. What are the differences between fine and commodity? Philosophy, scale, and compromise.

A big problem the new distilling movement has is a shoddy notion of philosophical ideals and absolutely zero chemical and biological control. With few exceptions, they have all pretty much only gotten as far as: “look mom, I made rum”. And of course it is not rum, which is a concept that pops up in the literature time and again, best reinforced by Arroyo. Not all things made from sugar cane products are rum and if they’re not rum, they are in the commodity category. The commodity category has things that aren’t fit to be called rum as well as things fit to be called rum, but not fit to be called fine. Right now we are seeing some of the most expensive commodity distillates ever produced hitting the market from the new distilling scene.

Skimmings communicate in a far greater degree than molasses the characteristic stamp to rum. A spirit made of pure molasses and water would scarcely be rum; and instances are familiar of molasses having been removed from one place and distilled at another, which, with different skimmings, have produced an entirely different rum. -J.S., 1871

Ideas evolved a bit and rum, according to Arroyo, starts with a rum yeast, and what is special about that yeast is that it takes advantage of precursors in the substrate to produce extraordinary congeners, of low frequency of occurrence, and of universal harmonic value, all the while limiting congeners like fusel oil which overshadow when in excess. Yet we’ve only learned all that recently by rediscovering literature that had been lost for decades.

Just like the chemical and biological aspects of rum production have a history, so too does the philosophical and that heritage goes back much further than anyone had recently thought. Just the other day, a paper turns up from 1871 with an author (J.S. also quoted above) describing the idea of forcing versus intercepting flavour. Though it is proto-philosophy, the concept sit parallel to the idea of wines of effort versus wines of terroir.

Only with recently revealed technical history could we read more of the story of the fine rums of Cape Verde because much of their unique character has to do with their sugar cane juice not being centrifuged and defecated like the rhums of Martinique.

Don’t forget that many of the fine rums of the last ten years from independent bottlers such as Plantation were not very conscientious nor produced with much enlightened philosophy. They were found art, accidentally over aged, and accidentally ending up extraordinary after missing their modest targets. Their architects weren’t part of contemporary culinary with their own twitter accounts, but were often government employees and at the most generous, many could be called outsider artists (brilliant and conscientious, but within a tiny bubble). The faceless nature and the way so many producers imploded is a big part of the intrigue for the sleeping relics they left behind. But on distilling day for the 1986 Barbados rum bottled by Plantation, if you said fine or asked about forcing or intercepting flavour, the Barbados boys would say: ‘the fuck you talk’n about?’ It was distilled like a brick house, but with commodity ambitions as the basis for some anonymous blend somewhere.

Anyhow, read Darnell Davis and marvel at his tracing the etymologies of rum and his tales of digging through the libraries of Europe to do it.

J.S. Tells of Rum, Jamaica 1871

Alongside Patrick Neilson in the 1871 edition of The Sugar Cane was this account by an author signed J.S. I’m supposed to be putting down my investigations on rum to focus on the Houghton Street Foundry, but I could not resist.

The J.S. account is of a slightly different perspective, so it may be helpful to comb through it and see how it lines up. J.S. seems relatively less focused on rum production and more involved with cane cultivation and sugar production. Half of J.S.’s article is about cultivation issues before going into rum production, but I’ll skip that.

Leaving the sugar to drain, let us return to the millhouse to collect materials for the distillery. Mill-bed trash, sour, or rat-spoiled cane, suckers, &c., are all collected and ground for the purpose of making rum. Then from the boiling-house is taken the trash and lees from syphons, and skimmings from the coppers. All these meet and mingle in a large receiver, or mixing vat, which is continually ebbing and refilling, and kept fermenting. From this a certain quantity is put in the bottom of each vat or cistern to be set up, generally about 250 gallons to a vat of 1000, which with 475 gallons Dunder, 200 gallons of water, and 75 gallons molasses, will make up a vat of liquor standing thus by Long’s saccharometer (which shows degrees of specific gravity above water, and about 7½ to 1 of Baumé’s scale):

For starters, these guys were smart and he goes on to crush math with fractions like a savant. Anyone in Jamaican operating at the birth of rum’s stylistic identity was well educated.

J.S. is also describing a system very much like Patrick Neilson’s where the trash cistern is being used as a sort of yeast/bacteria generator and that footing is used to setup the entire wash. He writes sort of clinically and does not sing the praises of the individual raw materials like Neilson.

The above should take about six days to ferment, and is an average specimen of the wash set and distilled here; but on each side of this average there are considerable variations, some setting at so low a degree of gravity that fermentation is over in two days—others so high that is may take two weeks. This can be done without materially interfering with the percentage of sweets added, or return of spirit produced, the dunder being the medium effecting this, which may be kept at any standard of gravity from 20 to 60.

Maybe we should reference Rum, Osmotolerance, and the Lash. Without changing the percentage of sweets, a.k.a. fermentable sugars, other variables can extend or shorten the duration of fermentation. Arroyo really pushes an understanding of this to the max.

Such differences in the mode of treating wash does not fail in producing corresponding variations in the quality of rums—that from the waterish and quickly fermented liquor being of a harsh and bare alcoholic odour; while the other, even new from the still, will smell mild and full-bodied. It is nevertheless asserted that the former turns out the more drinkable article by age, as is said to be the case of whisky of a similar stamp distilled from raw grain. Notwithstanding the superior character of Jamaica rum in general, there arises baffling dissimilarities in the flavour and value of rums made even on neighboring estates—the price realised for one being sometimes nearly double that of the other. That such differences would give rise to various speculations as to their cause, as well as endeavours at competition, is but natural to infer. Such endeavours have not been few, nor unattended in single instances with fair results, but the theories alighted on by experimentalists are varied and incongruous. The means adopted are principally confined to the treatment of the wash in fermentation. Pursuing the course indicated by the fact that better rum being producing by slow fermentation, the direction has been followed to the utmost limit consistent with a reasonable sacrifice of quantity and quality. Such sluggish fermentations are often induced as to present  not only unmistakable signs of a highly acetous, but an apparently morbose process, which instead of dissipating—as might be inferred of a rapid process—tend to fix, develop, or dissolve (as chemical investigation might determine) the aromatic principle (or substance containing such) constituting the valued flavour. Were the result attending this rather hazardous experiment always a success, we might be contented to abide by the conclusion that this aroma is entirely the effect of a certain process of fermentation; but as such fails to be the fact, the more natural supposition seems to be that it is a peculiarity incidental to certain soils, extracted principally by the albuminous matters of the cane juice and sent in the skimmings to the still-house.

#morboseprocess Here we she admission of “experimentalists”, probably of the like of Neilson, who are developing the early Jamaican rum process. At the very end J.S. also notes the importance of skimmings.

In commendation of this it may be stated that flavour is always strongest in the bottom part of the wash in the fermenting vat, when the albumen and yeast, &c., have subsided after fermentation. It is to be remarked, however, that rums of the most natural and most valued flavours are made in the most ordinary way, and without any effort of forcing, which fact directs and strengthens the belief that flavours may be intercepted, but not directly forced, by fermentation. I believe the water used in setting to have more connection in imparting flavours than is generally allowed. It is beyond dispute that the superiority of Scotch Glenlivat and Irish Poteen whiskies is owing to the soft, mellow, sweetish waters derived from surrounding peat bogs, and using in mashing and brewing. These whiskies are to all others what Jamaica is with rum.

A very subtle admission happens here when J.S. grapples with intercepting versus forcing flavours. My reading is that there is an admission of peculiar character other than esters which is rum oil. Esters are forced by the #morboseprocess while rum oil is thought to be intercepted and dissolved from products like the skimmings. Rum oil has been bred out of our rums but when you find it, you’ll know it. Esters can be faked in contrived ways, as I’ve stated so many times before, but rum oil is nearly divine. Rum oil is produced during fermentation through the hydrolysis of glycosides (a discovery first reported on this blog but pretty much stolen from the latest Cognac literature) and many variables such as a long fermentation, and even a resting stage, increase the potential to split the glycosides. Please see: Mezan XO challenge.

Skimmings communicate in a far greater degree than molasses the characteristic stamp to rum. A spirit made of pure molasses and water would scarcely be rum; and instances are familiar of molasses having been removed from one place and distilled at another, which, with different skimmings, have produced an entirely different rum.

This is a powerful statement that parallels much of what was said by Neilson and draws into question the greatness of New England rums. The current naive generation of new New England rums scarcely have any rum character and this I believe is what J.S. is talking about. However, decades later, Harris Eastman Sawyer would enter the fray in New England, and judging by his few writings as well as his sales to the tobacco industry, Eastman was able to make a rum purely from molasses that had that peculiar character.

Among other efforts to impart a flavour may be noticed that of adding certain odorous ingredients to the wash previous to distillation, or lucious fruits during fermentation. Of distillation little need be said. The apparatuses used are the common still for wash and generally retorts for the high and low wines. Low still heads are approved of as admitting more free passage for essential oils, but with these caution must be used in firing, so as not to force over bad oils which ought to remain in the lees, and at the same time prevent foul running. The running should be conducted slowly so as to cause the spirit to arrive perfectly condensed and cool. Flavour is always strongest in the first half of the spirit from the still, and it is sometimes the practice to put this up separately, and ship it under a different brand from the other.

For starters, we are catching up with some of Jamaican rum’s infamous  myths, but without much specificity. We also see that J.S. was conscious of the shape of the still head influencing the flavor of the distillate (low still heads). Foul running likely implies an overly rapid boiling creating foam that spills over through the condensor and into the distillate. Isolating for sale the first half of the distillate is a primitive form of super fractionation I’ve talked abut in the past where distillates are chopped up into more than the traditional fractions and reassembled as specific products. The big incentive of it here is because the taxes are so atrociously high and the market is fairly efficient. German buyers are happy to bid up the price based on how far they can stretch the concentrate, and the tax will be the same no mater what, so there is a big incentive to remove anything neutral from the rum. The reason this doesn’t really work in producing a truly great product is because the most valued congener, rum oil, is not in the first half, but rather a product that appears in the second half alongside fusel oil (hence benefit of colder fermentations).

That rum has not only been the staple and principle support of the many ill paying estates during bad years, but has acted indirectly as a barrier to the introduction of improvement in sugar manufacture, even on highly remunerative properties, there can be little reason to doubt. Proprietors when asked to adopt such and such an improvement, or send out certain new machinery, at once become jealous of the quality and proportion of their rum, and answer “no,” making such excuses as that they expect greater improvements to be arrived in course. The invention of the concrete process—the latest stride in advance—was not in the direction of Jamaica, unless for exceptional estates producing rum, so poor in quality as to be of the remotest consideration.

The concrete process is where cane juice is vacuum concentrated into bricks. No molasses is separated. Jamaica was very slow to adopt new sugar producing efficiencies because it, at the time, was far more successful in rum producing than anyone else. Producers were putting high value on byproducts like quality molasses or skimmings that were less rum beneficial in more sugar efficient processes.

Not only is ordinary rum netting £15 per puncheon, sometimes a more profitable article than sugar, but high classed brand at £18 to £25 per puncheon∗ in such cases make sugar quite a secondary consideration, and often attempt the turning of such an undue proportion of materials down to the still house as to seriously affect the value of the rum itself. So long as this state of matters continues, there is little likelihood of an sudden changes in our boiling houses here, yet it is to be hoped, as well as expected (especially should the recent favourable years continue, with returning confidence and capital to the island), that as the old taches and syphons become “burned out,” more advanced methods of manufacture will be adopted, having for their object the turning of cane juice to the best possible account, in the direction of its more legitimate end—namely sugar.


Trelawny, Jamaica,
23rd January, 1871.

J.S. appears to think that rum is morally inferior to sugar production and morality somewhat has an influence on the economics of can cultivation. This moral sentiment had profound influence on other islands and was the reason rum production never took off on Hawaii. No doubt there are quite a few other examples.

All in all, J.S. seems quite aware of all the ins and outs of rum production with an ear to the ground, but he is no experimentalist like Patrick Neilson. A deeply flawed moral conviction keeps his interest always with sugar over rum and that is just sad.

Patrick Neilson Tells of Rum (Like No Other), 1871

I’m supposed to be working on a new photo shoot for the Houghton Street Foundry, but I couldn’t resist sharing up this pearl of rum history.

A note from my archives which I had shared up the other day had a wonderful quote by Scotsman in Jamaica, Patrick Neilson. It was hinted that he wrote a great paper on rum in one of the very first editions of The Sugar Cane.

I will easily say that it is one of the most significant papers on the topic of early Jamaica rum. It is a ten page origin story that draws from his European experience, the opinions of the German buyers, anecdotes galore, and it just plain fills in a lot of gaps. Neilson’s pursuits are also aroma-centric and I think he is setting a precedent in the literature (1871).

Neilson tells of the mythic rum canes (which so far exist in reference nowhere else but this blog), early ripening canes having more aroma, and Bourbon cane producing his favorite rum. The German buyers paid the most for the first five batches of the season and we find out why. There are admissions of “lucious fruits”, the likely arrival at a pombe fermentation, small estates doing it better. Read it for yourself.

Neilson supports a big point that this blog has been driving for years, which is that distillation itself is no big deal and he glosses over it. Fermentation and the raw materials are everything. My Distiller’s Workbook has always aimed at giving a thorough understanding of still operation so that involvement can be deepened in the other stages. The still operator can be an intern while the fermentation chemist is everything.

Its 1871 and Patrick Neilson is expounding the virtues of slow fermentations and cool temperatures.

[…] quite the opposite to the system usually carried on, namely, the hurrying in of all material, keeping the vats boiling like a pot, fermentation over in three days, closed doors and a heated apartment, consigning all the refuse and bottoms to a dirty cistern, where all, or at least a considerable portion is in a manner lost.”

I would have thought by all I’ve read that the legendary long fermentations started much later but this is 1871.

In order to show the great difference that exists between quick and slow fermentation we have only to look at the method pursued in some parts of Germany for the production of what is known as Bavarian beer, which is the product of a very slow and protracted fermentation, combined with a low temperature, for a full description thereof I would refer to Liebig’s works—a few extracts here however will serve my purpose so far,

This is exciting to me because I want to know where the ideas came from. Now Neilson quotes Liebig:

“the wort after having been treated with hops in the usual manner is thrown into wide flat vessels, in which a large surface of the liquid is exposed to the air, the fermentation is allowed to proceed while the temperature of the chamber in which the vessels are placed is never allowed to rise above 60°. The fermentation lasts from three to six weeks, and the carbonic acid evolved during its continuance is not in large bubbles which burst upon the surface of the liquid but in small bubbles like those which escape from an acidulous mineral water, a great deal of yeast is deposited on the bottom of the vessel in the form of a viscous sediment; this precipitated yeast does not excite ordinary fermentation again, and when the yeast is used again several times in succession the temperature may be increased much higher.”

I highlight the whole quote because Patrick single it out (by now he is Patrick to me). This check list is on his mind and you see such differentiation of fermentation phenomena on the minds of other Jamaican rum chroniclers that came much later. Vat size and shape would become important and would be a factor others were in tune to as they pursued fermentation with symbiotic cultures.

The beer so obtained is entirely different and far superior to many other sorts; and if this superiority is got simply from a slower fermentation  then I hold that like results may be obtained in rum making.

Jamaican rum styles were not evolving out of the success of neglect or anything like that, they were being directly inspired by beer!

What in fact first drew my attention to seeking out a flavour in rum was the running I first got from what is known here as the dirty cistern, a receptacle for all the refuse, bottoms, &c. of the other vats; I was astonished to find at the can pit mouth, as the run came over, an exquisite flavour. I considered and said, why not make all the other vats, dirty cisterns, or at least to come extent, and I proceeded accordingly, with very happy results.

This is the very first experiment with cane trash and it has a time stamp and a first name. After this the ferments get a little more complex and feature more cane byproducts and ratios of cane byproducts as seen in the Experiment Station works.

I may state that the said dirty cistern besides being a receptacle for all refuse, is allowed to go on fermenting away, sometimes dead, sometimes alive, for three or four weeks; in fact, a sort of putrefaction goes on, and an acidity is produced which frees the aroma, hence a fine flavour when full.

This is some fine organoleptic investigation. What I think he is noticing is that fermentations are going on that produce all manner of fatty acids. Alkaline lime marl is also being added, but not intentionally as will come later in history. At this point its just excess from cane boiling. The lime alters pH, restarting fermentation when it runs away and becomes too acidic. The lime also has an affinity for shorter chain less noble fatty acids and it frees longer chain acids that were previously bound as salts. This is more pronounced as the cistern gets full of liquid and that is what Patrick is noticing. In the not too distant future they will know all the specifics.

Following up my ideas, I then proceeded to turn half of the vats, gradually increasing up to two-thirds, into slow fermentation, and commenced by adding material in small quantities to each vat. The vats were about six feet deep, holding about 2000 gallons. I only put in liquor to cover about two feet at the commencement and added from day to day as I saw them dying off, keeping them always gently excited till they were filled up. I kept them moving this way for two weeks, sometimes less, sometimes even more.

I see this as wildly important and I’ve been collecting these anecdotes about the very beginnings of the seasons where practices may differ from later on. Every detail influences the microbial community. Patrick may have been starting a fission yeast Pombe ferment as opposed to a conventional budding yeast ferment. Whatever trash he started with may have dropped the pH low even that an alt yeast took hold.

As these vats began to work I soon found a rich fruity odour pervading the house, and I then knew I had the right thing, which was confirmed at the can pit mouth.

On resetting up these vats I did not as customary, pitch the bottoms into the dirty cistern, but set up again on them, continuing to so for three or four successive occasions when the liquor began to get muddy and I had to throw them out.

What Patrick is describing here is a back slopping technique often used in Cachaca ferments. A microbial community will soon evolve to an equilibrium. The yeast though can get tired and they may require conditions better suited for reproduction.

I found at about the third setting up, a round from which I obtained the finest flavour, after that the vat began to get too heavy and sluggish besides acid. I then threw the whole away, dunder included, and drew from the other third, that is, I kept one-third of the vats working on the old system, for the sole purpose of obtaining a fresh and sweet dunder.

Without chemical control, they have yet to be working on continuous system and instead are on everything third batch you start again.

By setting up on these bottoms I extracted all their virtues, not so by a dirty cistern, it is far too clogged up, and there is not half enough liquor in it for the solubility of the precipitations, there is a loss there also, as the dunder has to be thrown away at every running of a dirty cistern.

This shows the more primitive system Patrick was getting away from. They knew there was alcohol in the byproduct and they periodically ran it through the still.

By thus working I changed the character of the fermentation very soon, only small bubbles working on the surface quite gently, something like an acidulous mineral spring.

Noticing something different, he may have found our hero Pombe.

When I wrote my first paper on the subject it gave rise to some comment—why could I only make two-thirds of my rum crop good and not the whole?

I highlight this because we may find that article.

Besides that, I then quietly withdrew all my low wine stills. I was the first to do this, but it has now become a common practice on many estates. I would however suggest that these low wine stills be redistilled—it would take away the low winey flavour.

This is a little hard to interpret and I think it means that they started to find, now that they were producing more aroma, more virtue in fractions further along the run.

In addition to what has been said, there are many minor details requisite for procuring flavour, none more so than getting plenty of Rum Cane liquor, that is the half rotten or rat eaten cane, unsuitable for sugar and generally sent to the still house, not at all for flavour, but from economical motives, however the bookkeeper often gets flavour thereby quite unwittingly. The rum canes have gone through a process themselves of a slow fermentation, lying in the field and yard, hence their efficacy.

This to me is among the most exciting parts of the paper because it discusses a tradition that may have been completely erased. If a microbial community needs to be created from scratch, this may be the place to look. It would likely be the subject of an awesome PhD paper. This also parallels whole cluster fermentation in wine grapes and is known to produce a distinct character with specific chemical markers.

I have known some estates making rum one year worth £25 in England, and the next only getting £17. I could trace it to the want of rum cane; when rum cane is not to be had, sweet cane liquor is as good only subjected to proper treatment.

Cane liquor likely being fresh sugar cane juice which brings its microbial community because it was not sterilized in the boilers like molasses. The experiment station documents decades later make use of lots of fresh sugar cane juice and if I remember correctly fail to acknowledge the rum cane. I suspect hat as more trained scientists entered the fray they absolutely could not rap their heads around rat eaten cane.

Another indispensable article is skimmings; a distiller cannot get too much of these. I have seen some estates giving away the half of them to the working mules, they were very probably throwing away £5 per puncheon; very few mules now enjoy that beverage, the value being better understood.

We all know of skimmings but we have not seen such an endorsement nor such an anecdote!

The skimmings are the fat or cream of the liquor, and it is for want of that commodity that our large distillers in the United Kingdom can only distill guid Scotch whiskey out of molasses, in place of rum. Skimmings are a powerful agent in fermentation, and vats set up with molasses alone will not yield nearly as much as when mixed with a proportion of skimmings. Skimmings have a very acid reaction.

Hell of an opening metaphor and “guid” is a little Robert Burns-esque slang sort of like guid enough for a drunk. Euphonically it explains itself (I consulted David Ferry who had a lot of fun doing the voices). What I have not found is a chemical look at skimmings. How do they boost aroma? Do they hold the mythic glycosides? New England rums, we must remember, had no skimmings.

I believe that temperature has something to do with making a good spirit,—”heat yer maut slow and ye will get the sweeter liquor” is an old Scotch saying, perhaps applicable here; it may be owing to this that our October brewing of ales at home are always the best.

Oh yeah? Tell us more…

I often thought that in the beginning of the crop here, that is after the first round of vats, that the best rum was made, owing to the temperature—January being very cool. I have also heard German rum buyers here say that they have engaged whole crops of rum on the faith of the first five puncheons submitted to them, but towards the end of the crop they were miserably disappointed.

These anecdotes are treasure.

Canes also, scarcely ripe, will produce much more for the stillhouse, and bye the way, flavour also; even cane tops in a dry season are a very good thing for rum—just as good as rum cane, sometimes better.

Oh really Patrick? [bats eyelashes]

What also affects cane juice, but in flavour of the stillhouse, is the distance sometimes that the grinding apparatus is from the coppers, especially where there are windmills, the liquor has often to travel 200 yard in an open gutter. That the manner of boiling  cane juice does affect after products is shown by the fact which I heard stated on good authority, that where on an estate usually producing a good rum, they were compelled, owing to an accident in their machinery, to send their canes to be ground in a neighboring estate, the rum turned out perfectly different.

Patrick and I may or may not be half way through a Mezan XO challenge. Write drunk, edit sober.

What sort of cane is most favourable for good rum it would be difficult to say, but I certainly prefer the Bourbon.


Leaving the fermentation house, we come to the last process in rum making, namely, the distillation of the fermented wash or liquor, this is so simple that no description is necessary. The still in use here are mostly those having one or two retorts, which produce rum at one distillation, there are a few estates yet using the old single still, which involves three distinct distillation and great extra expense for fuel and attendance. It would be difficult to say which still produces the best rum. One would imagine that with the retorts great opposition is offered to the essential oils, or flavour coming over, and yet some of our best rum are obtained by retorts.


I have seen some bookkeepers using the spent lees of the retorts again, saying they get better returns; there never was a greater fallacy, and of all things I would eschew this, the low winey poison is just what I would seek to avoid. It is amusing to hear the different opinions about loading the retorts, the fact being that as long as the induction pipe is covered it is all the same, the alcohol will come over, it may be either in rum or low wines. To save trouble it is best to keep strong spirit in the retorts, and when kept up a better spirit is got. Consign weak rum to the low wine cistern.

When Patrick says spent lees of the retorts he is describing a fraction that doesn’t usually have a name. He says lees but there are no yeast present. This fraction is the non-volatized part of a fraction already distilled. It is mainly water, fusel oils, and less volatile fatty acids. When I’ve discussed the loops of fraction recycling in the past, this fraction is a point where things exit the loop and are not recycled.

I will close my paper with a few general remarks on the subject. It has been observed that few very large estates make fine rum—always the smaller ones. I account for this by the bookkeeper being obliged to keep pace with the large crop, and in consequence, hurry on all his materials. Molasses, for instance, should not be used till they are a week or two old, they oxydize as it were, and certainly change their character. Perhaps it is from other causes that our “we still whiskey” at home is famed.

Another important matter that will affect rum is the quality of the water used. I believe that the name of some our more celebrated brewers and distillers in England depends upon this.

Here we have Patrick christening the category of fine rum (as opposed to commodity rum) in 1871. I try and reinforce these as the too highest level categories of spirits. Mixing and sipping are cliches that should die as well as industrial and artisanal. A commodity producer can produce a fine product even on industrial equipment.

Fine and commodity also better capture quality for purpose and justify the existence of other styles. I’ve discussed in the past that some rum producers have realities we fail to recognize. Short fermentations often exist because of pressure to move substrate along. The molasses is stacking up. These producers are not cheating anyone and they price their products appropriately. We undervalue commodity producers and as urban American hipsters fail to recognize that the laborers of the world need an affordable drunk.