Narrative of the 1975 Rum Symposium

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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.

As usual another cache of forgotten rum papers showed up that paints a narrative of rum advancement mid 19th century that is seldom looked at. It seems to be far easier to study much older periods. This collection of articles was assembled for a symposium held in the West Indies.

I’m having a busy week between the machine shop and the restaurant so I’ll just put this out there then maybe follow up on it later.

The Analytical identification of rum / R. J. Mesley, D. B. Lisle, C. P. Richards and D. F. Wardleworth
Set Level: Annales de Technologie Agricole. N.º 3-4, vol. 24 (1975), p. 361-370

This paper is part of the beginning of the chromatography era and of course rum led the way. One reason spirits finger printing was important was because of all the trade rules governing the movement of rum. If you could confidently identify a rum, there would be less chance of theft (because it had to turn back up again) or illegal aliens and rum border jumpers moving around. All analysis was conducted in a “revenue protection laboratory”. For a long time this analysis did not help advance production but was merely for revenue protection.

Formation of acetals in run : a kinetic study / K. Misselhorn
Set Level: Annales de Technologie Agricole. N.º 3-4, vol. 24 (1975), p. 371-381

The chemistry in this paper is kind of heavy. I guess the amount of acetals should be at a predictable level when at equilibrium with a given amount of aldehydes, but that isn’t always the case because of the formation of semi-acetals. The paper notes that there is dispute on the organoleptic importance of acetals. Some downplay their importance while others say some are very important to flavor. I think Piggot wrote about their importance. I don’t know enough about them.

The rum pilot plant of the agricultural experiment station of the university of Puerto Rico : past, present, future / A. E. Molini
Set Level: Annales de Technologie Agricole. N.º 3-4, vol. 24 (1975), p. 391-396

This summary of the Pilot Plant is particularly important and some of its intentions are revealed. It also helps contextualize Arroyo whom the torch was passed from. Arroyo produced a lot of “leads” for further investigation, but I don’t think the Puerto Rican industry, with its massive responsibilities (that we typically fail to recognize), were interested in making complex, fine, full bodied, Jamaica-type rums. I think their work paved the way for a lot of the rums that would give the category a bad name. There were investigations of super clean ferments using antibiotics and chemical additives, investigations of very high alcohol ferments with intense optimization of fermentation variables. At the same time there research made the industry very environmentally friendly.

As we will see in another paper, there was intense automation and optimization of high proof distillation. The paper has some brief summaries of their achievements and a unique one is that of ageing where they realize that even with all their scientific resources, there is no substitute for natural ageing in the barrel.

This paper is well worth reading and I do have the annotated bibliography of the Pilot Plant which I will eventually start collecting.

Possibilities of utilization of butyric acid bacteria for rum making / S. Nemoto
Set Level: Annales de Technologie Agricole. N.º 3-4, vol. 24 (1975), p. 397-410

Wildly interesting, but sadly a very poor scanning. Arroyo’s ideas seem to have made it all the way to Japan and the Japanese made super full bodied rums even though they weren’t rum drinkers! They made confections! They were even investigating Pombe yeasts! “Furthermore, Japanese do not drink rum so much. […] After the Second World War, goods for daily use were insufficient and their qualities were poor. Materials of confectionary, such as butter and wheat flour, were not an exception. Heavy rum was used in order to improve the taste and flavor of cake made from those bad materials. Thus, rum has been developed not as a drink, but as a confectionary use, and in Japan heavy rum was wanted. […] We had to study rum making under very different conditions from West India.”

The world is full of lost rums.

What is to be found in literature about rum production that is more than 300 years old? / H. Olbrich
Set Level: Annales de Technologie Agricole. N.º 3-4, vol. 24 (1975), p. 411-420

This paper is of wild importance and amasses a bibliography of 150 sources, much of which are in German. I find myself sympathizing with the author a lot. And he hypes my home boy, Mr. Motherfucking Pombe, Percival Greig.

“It was not until a century later that the Englishman Percival H. Greig, 1893-1895, followed with systematic results on rum manufacture. Before going to Jamaica, Greig acquainted himself with microbiological procedures, aided by the Danish scholars Hansen and Jorgensen in Copenhagen. In 1895 however, his interest in publishing any work of his was brought to a close with three papers. Greig himself had become a rum manufacturer.”

So I am acquainting myself with microbiology procedures and walking a similar path.

“In 1936, Greig’s work was still reviewed to a substantial degree in an extensive paper [where is this paper?!], as the basic position of science regarding rum manufacture. So no abundant material is to be found in literature about rum manufacture until nearly the middle of our century. In the last decades, numerous circumstances have influenced both production and market development, as well as yielding some scientific papers. It is an irrefutable fact that a library is cheaper than a laboratory [emphasis mine] and that inquiries are far less costly than investments in development work which is already being carried out elsewhere. By means of thorough information regarding the basic position of science and technique, irrational brain-work is avoided, fruitless researching and inventing activities are prevented and the squandering of economic power and capital is hindered. With other words : Ascertainment of which results and suggestions have already been published in order to solve a problem, serves the rationalization and increase in the productivity of science and practice. Unproductive searching, idle effort and erroneous investments are thus avoided. For a sequel to the examination of literature work, which is sometimes unjustly underestimated, American atomic research offers an example which should be a warning; at an expenditure of vast sums of money, problems were supposedly dealt with, for which complete results were already to be partly found in literature.”

That language! And did he just compare rum research to nuclear research, fucking profound!

And of course Olbrich provides new references to track down.

Production of light-bodied rum by an extractive distillation process / E. D. Unger, T. R. Coffey
Set Level: Annales de Technologie Agricole. N.º 3-4, vol. 24 (1975), p. 469-495

This is a very complex paper and even if you cannot wrap your head around all the science, you can see massive automation at work. You can also see the birth of spirits made from sugar cane that some like Arroyo would not call rum. For starters, this paper explains how by using computation they can take a beer with a given set of congeners then predict what the output will be given the continuous stills tuning options mainly concerning fusel oil. This explains how a bespoke fermentation for Ron del Barrilito, or even any heavy rum within a producer’s portfolio of other lighter rums, could be spliced into the feed and variables immediately adjusted to give a lower proof ferment with a different level of fusel oil reduction from the usual. This does not give the distiller unlimited potential to pick and choose congeners, but it does give more options to maximize the potential of the still.

Reduction of fusel oil during distillation is shown as a big focus of the paper, but what Arroyo has taught us is that reducing it during distillation jeopardizes reducing rum oil which is the hallmark of rum (yet is seldom discussed). For heavy rums according to Arroyo, fusel oil should be reduced by yeast selection and fermentation optimization. Distillates produced as described in the paper are sort of the antithesis of the Arroyo teachings and are something else masquerading as rum. Yet its all wildly advanced and of course applied to rum first.

Facts about Sugar, 1940, Volumes 35-36, 26-? (part I already got), 35-? (start of part VI), 64-?;id=coo.31924054773571;view=1up;seq=7;start=21;sz=10;page=search;orient=0

Ageing, Accelerated Ageing, & Élevage ==> Lies, Damn Lies & Statistics

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Aging, maturation, curing, whatever you want to call it, is a hot topic these days. Many labels across many spirit categories are dropping age statements because they cannot keep up with soaring demand and many new entrants to the market are considering fake ageing techniques associated with a bygone era. I thought it may be fun to take a look at Arroyo’s progressive musings on the topic as he attempted to reform the sprawling rum industry.

The chapter on curing in Studies on Rum is pretty spectacular. For this conversation, it makes sense to start at the end:

We shall now close this chapter on the maturing of raw rums by touching lightly on the matter of accelerated curing of the raw distillate. Not all, or rather few, of the rums in the market have passed through a curing process such as we have outlined above. Our era of acceleration and impatience in all affairs of human endeavor would not allow of an exemption in the case of rum making. On the other hand, the ever increasing demands of the trade, the lack of adequate working capital, the anxiety for immediate returns, immoderate and unfair competition, and many other influences of business, compel the manufacturers to place their products on the market in the shortest possible time. As a direct result of the above-mentioned conditions, accelerated or quick aging processes have been developed, and are being developed all the time. There exist practically as many “secret methods” of artificial curing of rum as rectifiers are engaged in the business. Judging from what has been accomplished thus far, and from the nature and quality of the “rums” thus produced, the writer’s opinion is that the results obtained are very mediocre and unsatisfying; leaving the problem of artificial rum curing an open question.

What was outlined in the chapter was pretty much ageing as we think we know it, but as claimed few practiced it as of 1945. Puerto Rico was not the typical rum producing island as pointed out by Peter Valaer in 1937 so the local products being sampled by Arroyo are no exhaustive survey of the state of all rum production. Other islands were exporting tons of product to be aged in Europe so what was left for domestic consumption was likely another story.

Processes for rapid curing may be divided into two general classes: (1) Those merely tending to accelerate the reactions and changes occurring during natural ageing, and in this way accomplishing maturity of the raw product in a short time; but without the addition to the raw of extraneous substances, the so-called carriers of taste, aroma, and body. (2) Those intended to accomplish the results mentioned under (1); but using besides these extraneous matters, imparters of taste, aroma, and body. The method used under (1) will fall into four main divisions: (a) moderate heat treatment or intense cold treatment; or alternate treatments of heat and cold; (b) treatment with compressed air; oxygen, hydrogen peroxide or ozone; (c) exposure to actinic rays; (d) electrolytic treatment and use of catalysis. Methods under (2) above, may include all of the methods under (1), besides the addition of flavoring and aromatic substances for development of taste and bouquet. Among these added substances we may mention; (a) various types of sweet wines, among which the various “Moscateles” and “Málagas” from Spain; and prune wines from Scotland are much in vogue; (b) infusions of herbs, leaves, barks of trees, roots, etc. etc.; (c) alcoholic and aged fruit extracts, among which peaches, prunes, figs and apricots are much used; (d) artificial  essences of rums or brandy; (e) various natural and synthetic essential oils, and flavoring extracts as cassia oil, oil of cloves, artificial or natural vanilla flavor, oil of bitter almonds (free of hydrocyanic acid); and various sugars, as sucrose, dextrose, sugar cane syrup, maple syrup, and bee honey.

In this guise, beverages are made that although more deserving of the name of cordials or liqueurs, are labelled with the name of rum. We believe that all of this is avoidable and unjustified, should more and better attention be bestowed on the different stages of rum manufacture, and especially on rum yeast selection. Governmental regulations and inspection of the rums produced and sold in the local and United States markets wold be a great help towards fostering the interests of the industry, and securing the genuine article for public consumption.

Well, there wasn’t anything too new there, but it is a great organization of the concepts in the midst of when it was all going down by a scientist with a privileged vantage point. An item of trivia that I didn’t know about was that the prune wines came from Scotland. The paragraphs just tell semi specifics on fake aging and I caught most all of them in my investigation of Wired’s look at the Lost Spirits fake aging reactor. Not much has changed.

Lets back track to the beginning of the chapter and see if Arroyo gives anything helpful to frame rum maturation:

Is the expression “Aged Rum” equivalent to that of a “Matured Rum”?

We have observed that a great majority of persons use these two expressions as synonymous but they are mistaken. When one term is used as equivalent of the other we are merely confusing the end with the means, for really, maturity in the rum is the end sought, and ageing is one of the means employed towards the obtention of this end. Now then, although usually an aged rum is also matured, this sequence does not follow necessarily, nor there exists a definite lapse of ageing time at which the condition of maturity may be said to have been reached in all cases. On the other hand, a given rum may be matured without necessarily being what is commonly called an old rum. If the quality of maturity depended only, and exclusively, on the amount of time the rum had been kept aging, then perhaps the two expressions could be used indistinctly, but it is not so; ageing being only an important factor in the process of maturing. There are other, for instance, the potential capacity and adaptability of the crude rum or raw distillate to acquire the state of maturity. In our opinion, this factor is as important, or more perhaps, than that of ageing.

Profound! We want it so simplified, but it is not so simple. I am personally really enjoying the collapse of the age statements because it is really a test of the market’s ability to truly appreciate spirits. And, as usual, Hemingway would be siding with me. Can the market actually notice and evaluate maturity? No! Has it borrowed anything useful from wine appreciation? No!

With wine, we make our own pronouncement of maturity and as the age statement grows, so too does skepticism that it will be intact. We also value multiple levels of maturity. Luckily the bottle is its own curing vessel and we can leave our other bottles where they lie if they need more time. Wine gets too mature often and the majority of collected wines actually die in the cellar. I just drank an expensive Martinique rhum the other day that I thought easily spend too much time in wood. It was way too obviously tannic and that feature was a distraction from the aroma.

Notions of maturity will always be deeply personal (your own stance) and based on the idea that flaws only form when we have enough education to attach the symbolic tags of regrets or missed opportunities to specific sensory details. Maturity relates to the unsexy concept I use all the time that is the frequency of occurrence of sensory features. Wines become mature as they migrate from ordinary to extraordinary with a decreasing frequency of occurrence of sensory details. After a peak, they return to the ordinary but with a growing sense of regret and missed opportunity. With wine, many of us hold the same stance on maturity and there is consensus on what is truly great, but with spirits at the moment, few attain a vantage point to make sound declarations. Life is short, the art is long!

It may not be impractical to start differentiating a curing stage from an ageing stage and wine can help anchor the concept. Curing could be the stage when a wine or a spirit goes from inharmonious to a commonly accepted harmony. Wines cannot be enjoyed immediately upon the completion of fermentation and have to go through a stage (with its associated techniques) called élevage. Some will even say it is not wine, but merely fermented grape juice until it goes through the process. Ageing would come later and a true connoisseur should be able to appreciate the wine at multiple places in its ageing journey.

Spirits, some others maybe more so than rum, also go through élevage. This may most closely pertain to the transformation of specific congeners like the reduction of ethyl acetate and acetaldehyde. Where lees contact or micro oxidation are techniques of wine élevage, charcoal filtration or as we just found out, specific watering regimens (if not also reflective fermentation adjustments) are among the techniques spirits employ. It is probably safe to categorize caramel and added sugar as a heavy handed élevage technique.

As an illustration, let us take up an imaginary case of two raw rums and called them “A” and “B” respectively. Both raw rums are set to age in the same kind, size, and quality of barrels, and under equal conditions of temperature and relative humidity. At the end of one year the two rums are examined by the usual tests for maturity and it is found that rum “A” has already acquired the quality and general conditions inherent to a matured rum; while rum “B” has not quite reached this conditions. Rum “A” is then bottled, and the ageing of the “B” is continued, till at the end of another six months we find that it also has reached the state of maturity previously observed in the case of “A”. Would it be fair to consider sample “B” as more matured than sample “A” for the mere reason that is has aged for a longer period? Could we be justified in acclaiming rum “B” as superior to rum “A” for the mere fact that it cost more time and money to impart the characteristics of maturity to it? Evidently not. If at all, we could say that “A” was superior to “B” in an economic sense since it acquired maturity in two thirds of the time required by sample “B”.

This might be the example that the average consumer (where they stand now) needs, but hopefully we can quickly grow a little past that. In Arroyo’s era, rums were naively being produced without knowledge of options while the aspirations of each rum were roughly the same. Wine went through this phase lasting decades after prohibition ended and Amerine, Tchelistcheff et al. filled the role of Arroyo and taught us our options.

Older practices, contrary to Arroyo’s, were not without merit, and that was only realized as the aspirations diverged to where there was a fine market alongside the commodity market. A big flag to be raised was whether anything was compromised by designing a rum to be matured quicker? And how does it compare to wine design? There is a wide spectrum between building a wine like a brick house that can age forever and building a wine like a FEMA trailer. Rum aspirations are finally solidly diverging and we can now reflect back on all the available options like the wine industry has done in the last leg of its renaissance. Some of Amerine’s teaching had staying power across all styles of wine while others were relegated to low risk, massive volume, jug wine production. Rum has gone through all the same phases, we just haven’t noticed. With enough scholarship, some day we will be able to get really specific.

This example has been presented so that the reader may clearly grasp the meaning of ripeness or maturity of product as distinguishable from that of age of product. It is not fair to use solely the time a rum has been in the curing barrel as a criterium of its goodness or of its pretended superiority over a similar rum that has been less time ageing in the curing barrel. Hence, any standard of rum quality based solely on the lapse of time the different products have been aged, would be not only unscientific and erroneous, but also decidedly unjust. It is not the age of the rum that is bought and paid for by the public, but the genuine characteristics of body, aroma and taste that on reaching maturity a rum acquires. The time required by different rums to reach this state of maturity during ageing will depend, other conditions being equal, on the type and the quality of the product as a raw distillate.

This is where we need to get to. We get stuck on age statements and then we get stuck on what type of still was used yet rarely delve deeper into the parameters of still operation. Sadly, we never get to fermentation parameters or yeast type. I was really surprised that when I started writing about Schizosaccharomyces Pombe as a rum yeast, not one enthusiast in my circle knew of it as an alternative to budding yeast.

But this is rum and it is so varied, does any of this apply to Bourbon which is not so varied but losing its age statements? I do not know the answers but these are things we can start to think about. Bourbon has privately if not secretly seen astonishing technological advancements in the last twenty years. From what I gather, all the advancement were about monitoring traditional practices in an effort to stay consistent as production grew to meet global demands and hit sustainability targets. There may be a new effort from all the data to sculpt next generation products. Bourbon producers may have finally gone through all the Olympic trials with prospective yeasts as well as mastering congener creation to hit maturation targets faster. Bourbon producers may have taken the hard road, the Arroyo road, through massive research efforts and arrived at the 21st century.

Our researches on the question have demonstrated that great variations and difference exist in the capacity and adaptability of different raw distillates to acquire maturity. There are some capable of reaching this desirable condition in from one to two years of ageing, while others may require twice, and even thrice this time.

It is really amazing the little importance that is generally conceded to the quality of the raw distillate in most rum distilleries. Instead of trying to produce a raw spirit that would need the least trouble in treatment during rectification before finally bottling the product, producers spend their energies and efforts in finding new, more complicated, and laborious methods of curing the defects of poorly fermented and worse distilled raw spirits.

This may still be the case, but that will change when we all go post-Kavalan! I promise to some day elaborate.

And yet, to our view, the future of the rum industry is dependent, in its technical aspects at least, on the production of better raw spirits, raw rums that on account of their well-balanced chemical composition and excellence of physical and organoleptic characteristics, will require but little ageing time to acquire maturity.

Towards that goal a great part of our efforts have been directed, and we have found that the obtention of maturity is not due to one single cause, as for instance ageing; but that this final result is obtained through a happy combination of many factors which begin operating with the choice of fermentation agents and raw materials and end with the bottling of the product for public consumption. Every one of the different stages through which the product must pass before reaching the bottle, shall impart to it favorable or unfavorable conditions and characteristics towards the obtention of maturity. Hence, the final success or failure will depend on the manufacturer’s ability to employ those methods and technic that better and more efficiently contribute to the rapid acquirement of maturity.

Of some such methods we have been treating in the past chapters, and in this one we shall consider the phase of rum manufacture that supposedly bears the greatest influence on the subject under discussion.

Having thus obtained the rum in the raw state through the process of distillation it becomes necessary to develop to the utmost the inherent characteristics of a good product. This is secured by the process known as curing or maturing. Here we wish to state emphatically that by this process we do not mean converting a bad product into a good, wholesome one. Not by any means. The rum which is bad in its raw state will continue to remain so, no matter which is done with it, or to it. Proper rum curing is not a process to change or transform, but to develop and further enhance the latent qualities already existing in the right kind of raw distillate. Of course, a poor raw rum may be made to improve, but it will never be converted into a first-class beverage with distinctive seal of excellence through the curing process, whether the natural or slow, or the artificial or rapid curing be employed.

We all know, not all wines are age worthy. I probably don’t need to say much more so it is probably safe to stop there.

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Aroma Breakage and Rum Design

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Arroyo spends a lot of time discussing the topic of of aroma breakage due to diluting spirits with water. This is a curious topic I’ve never seen discussed in other research papers. I suspect this is because it is so hard to quantify. Apparently, the sudden shock of adding water to spirits, particularly rum, because much of its character is dependent on esters and rum oil, is capable of splitting the esters via hydrolysis and possibly precipitating aromatic substances as salts.

The ideal raw distillate, however, would be one needing no dilution or treatment of any kind before proceeding with its curing, either slow or natural; or accelerated or artificial. These conditions are attainable through proper yeast and raw material selection, appropriate methods of fermentation and post fermentation treatment of the beers; followed by carefully controlled distillation technic based on the principle of selective extraction. Present manufacturing methods with few exceptions, have not come to this high state of development as yet. Hence, mention must be made of the important changes occurring during the diluting, or the diluting and carbon treatment process during rectification.

I was first casually introduced to the topic many years ago by Ed Hamilton who explained to me the phenomenon as a past problem with Martinique rhums shipped to France for bottling. According to Ed, these rhums would be improperly diluted, rushing the process, and the aroma would be detrimentally effected. The science on the topic so far is not as easy to fully explain as I’d like, but there is one overall solution pointed out above and that is to distill at lower proofs so much of the water is already integrated. Easier said than done, lets let Arroyo drop a little more science:

When a freshly distilled rum is diluted, its chemical composition as well as its physical characteristics are affected. The action of the diluent is felt to a greater or less extent, in accordance with: (1) original proof at which distillation took place; (2) chemical composition of the original distillate; (3) nature of the diluent, and manner in which it is applied. The deleterious action of rum dilution is twofold: chemical and physical. The first consists in a dissociation of part of the ester content through the hydrolytic action of the diluent acting in an acid medium; the second operates by salting out or separating certain essential oils through shock, and by the lowering effect on the alcoholic concentration of the raw distillate through the addition of the diluent. Among these oils we have some of the most valuable  natural constituents of a genuine rum. When the raw rum has been distilled at a very high proof, say between 170-180 degrees, a very large amount of diluent must be added in order to bring the proof down, say to 110 degrees. Now, the more diluent added the stronger will its hydrolytic effect be on the esters present in the raw distillate, and the stronger will be the tendency toward separation of essential oils. Hence, the caution previously given in the chapter on rum distillation that rum should be distilled at the lowest possible proof compatible with high quality of distillate. When the original chemical composition of the raw rum in its relation to the process of dilution is considered, it will readily be seen that the higher the free acidity and the ester content of the raw distillate, the faster and the more intense will become the hydrolyzing effect of the diluent on the ester content of the raw spirit. The same holds true on the salting out of valuable essential oils.

Lets stop him for a minute. It appears that the fullest flavored rums have the most to lose. It also seems like little inhomogenous zones get briefly created in the spirit where there isn’t enough ethanol to keep certain things in solution like the rum oil and, though brief, it is enough to shock stuff out. With the esters it is a little different and my favorite explanation of ester hydrolysis comes from Peter Atkin’s Reactions: The Private Life of Atoms. What I would think is that everything would eventually come back to equilibrium and that would easily re-dissolve the rum oil. I guess it doesn’t happen fast enough and there is a danger of stuff getting left behind when spirits are being only temporarily held in a vat that needs to be turned over for another process.

The nature of, and manner of adding the diluent, will also become a factor of importance during the process of dilution. There are at least six classes of diluents commonly used for this process: (1) ordinary tap water from the city mains; (2) well water; (3) rain water; (4) distilled water; (5) chemically treated water; (6) alcoholic solution in distilled or rain water, previously cured by either natural or artificial means. This last mentioned diluent is the least harmful and best recommended for this purpose, but is the one less used on account of the trouble of preparing and storing under suitable conditions large quantities of these weakly alcoholic solutions. Good practice should restrain the number of diluents to be three of the six mentioned above, and these should include; (1) distilled aerated water, (2) rain water, and (3) alcoholic solutions. Of the two plain water diluents, rain water is to be preferred, as it contains plenty of air and, therefore, lacks the flatness of taste peculiar to distilled water. Thoroughly aerated distilled water has the advantage of being readily available at all time. Diluting with aged mixtures of alcohol and water, or rum and water, will be the best method to follow; but as explained before, this method has its shortcomings especially for the large producer.

I remember reading this and wondering if Arroyo’s ideas like the ethanol-water mixture were arm chair ideas, dreamed up but never tried, or if anyone got it off the ground. Could it be worked into a strategy that would give a small producer an advantage when they typically lack any advantage due to scale? I could see column distilled relatively light rums being easily diluted much under 40% and then averaged up with stocks of aged, extra heavy, pot still spirit (to protect the pot still spirit which has more to lose). Sadly, I suspect not many small new Continental producers are making anything at risk of aroma breakage or using that template.

Now, whatever the nature of the diluent used, the manner of its application will have considerable influence in the extent of ester hydrolysis, and especially as to the degree of separation of valuable essential oils constituents. Cold diluent, suddently added in bulk or added in a very short period of time, will prove the most harmful. The opposite conditions of applying the diluent, that is, slightly warm, slowly and in an atomized form, will prove the least harmful.

The water so many distilleries use is at the mercy of the seasons. They aren’t really in a position to raise a large volume of distilled water much above room temperature. I suspect the cheap alternative would be to use the still’s condenser as a heat exchanger and warm diluting water during distilling runs. I can’t imagine rigging up a atomizer with an agitator would be too difficult.

In the course of these studies on rum we have observed that the harmful effect of the diluent in rum diluting last over an appreciable period of time, never less than for three moths, and extending up to six months. It is really a very important matter that has been lightly, too lightly, considered up to the present time.

Whatever vats you have, you’d definitely need back sooner than three months and whatever precipitated would not be evenly distributed between the barrels or bottles. Whatever is precipitated could also be left as an oil clinging to the side of the vat. If the tail end barrel did get an appreciable extra quantity to try and re-dissolve it may not do it properly. Many blending practices where spirits are briefly re-barreled after marrying may be related to the concepts Arroyo is presenting. Whiskey’s may have different congener sets, but they may also be subject to similar forces.

Its will be noticed that strong dissociation of the ester molecules occur in every instance after the raw rums have been diluted, and that this state of original esters hydrolysis is not ameliorated even after three months of curing in an oak keg. The ester loss through hydrolysis is heavier in those rums originally high in ester content. Organoleptic tests on the undiluted and the diluted sample are consistently in favor of the former. Hence, rum dilution is really a complicated problem, and the ill effects of dilution interfere also with the proper and expected progress in quality during the first few months of the curing period. If to obviate the ill effect on the curing of the raw rum during the ageing period occasioned by the diluting process, the raw rums are barrelled at the high proofs of distillation, nothing is gained in the long run; for if it true that it will mature quicker during aging in this case, it is also true that its proof must be lowered before it is bottled up. When diluting the cured rum, the effect of the diluent will be more disasterous even than in the case when the beverage was diluted as a raw product. These considerations make the problem of dilution an arduous one. The solution must come during the distillation stage of rum manufacture. Raw distillates much be distilled at low enough proof so that no dilution, or at least very little dilution should be required during rectification and curing. And this must take effect in such a manner that the quality of the commercial rum shall remain unimpaired.

I have a feeling Arroyo was not always popular because he was usually advocating taking the long road and being thorough. To distill rums at a lower proof you’d have to design fermentations worthy of a lower proof. Or you might not have to if you’ve got the time. Arroyo mentions that rum, unlike a whiskey, can be enjoyed right from the still and will have no objectionable roughness like a white dog. On the other hand, Peter Valaer, in 1937 for an IRS survey, describes the legendary extra aged New England rums as being rough right from the still and distilled at 60% which is considered fairly low. Valaer also briefly mentions the use of “pure culture rum yeasts prepared from a single cell in some of the most scientifically controlled rum distilleries” in the U.S. Who knows if U.S. producer’s like Felton & Son’s conducted their own Olympiad to select a champion rum yeast, but it does look like they had the technology. I’m not sure if they used a Pombe yeast because I have not been able to find hints of their fermentation durations which would imply an answer.

Many spirits out there distill at curiously low proofs such as cachaça and many tequilas. They raise the question, are these cruder spirits like the New England rum Valaer describes or are they produced from unique ferments with less objectionable congeners than the average whiskey ferment? The answer is probably the latter. If one tried to optimize a fermentation to distill at a lower proof, what would it look like?

The answer lies in limiting ordinary esters and short chain fatty acids typically separated from the hearts fraction by the heads cut as well as limiting fusel oil which is hard to eliminate during distillation because it risks reducing rum oil. Fusel oil in rums is best reduced by careful yeast selection and then careful optimization of other variables like fermentation temperature with a lower temperature typically correlating to less. Fusel oil production tests were part of the yeast Olympiad I described recently.

Excessive ordinary esters get reduced in the ferment by salting them out. Short chain fatty acids like acetic and formic have a higher affinity for alkaline substances than longer chain fatty acids and thus combine to become non-volatile salts. If this is done with precision, which basically requires analysis and systematic trials, there will be less objectionable congeners in the ferment and distillation can proceed at a lower proof incorporating more water. Extraordinary esters of a lower frequency of occurrence, that form in both the ferment and the still, will suffer less occasion to split apart. New England rums in 1937 may not have been benefiting from the careful pH buffering that Arroyo was using to distill at lower proof. Harris Eastman Sawyer, who I identified as the architect of modern New England rum, sadly died in 1911. Though he was progressive, he was not likely to be that far ahead of anyone else.

By this point, most of you are probably thinking: why don’t you just super fractionate as explained previously, over dilute the central neutral fraction which is taking Arroyo’s advice of diluting with an ethanol water solution and see if that keeps more of the esters together? I didn’t realize it was that obvious, but what is left is to simply put it to the test and see what happens. And to hope the logistics aren’t a deal breaking nightmare.

Even more of you are probably thinking: where is Lost Spirits during these recent revelations on rum design? Lost Spirits has put most all their emphasis on post distillation curing ideas thinking that that is what makes a rum great. Arroyo would probably laugh them out the door. He time and time again explains that you need a distillate worth maturation to even bother, and there is little emphasis on that (so far) in the Lost Spirits camp. You also need to get a well crafted ferment to get a distillate worth a damn. But if you could bring all those things together it may well be more worth accelerated maturation and I hope they do. On the other hand, if you really nailed all those processes, you’d probably not feel the need to accelerate anything.

One of the major things I’m forgetting about maturation is that a significant change, according to Arroyo, during the first legs of curing in a barrel are excessive ordinary congeners, with a high frequency of occurrence, namely ethyl acetate and acetaldehyde, actually evaporating with the angel’s share because they are so volatile. Accelerated maturation techniques, like that of Lost Spirits, have no angel’s share and cannot benefit from this mechanism. If they need the same effect, they’ll have to spend more time with their ferments. If they develop spirits with significant ester contents which is their goal, I hope they are taking all precautions to prevent aroma breakage when they get diluted to drinking proof.

Next up will be Arroyo’s thoughts on curing, he didn’t like the term aging, and the ideas are more relevant now than ever.

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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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Team Pombe and the Yeast Olympiad

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I think it is finally time to delve into some yeast topics regarding rum. I’ve sort of avoided it though Arroyo states you should always start with yeast selection. Factory design and equipment purchases, Arroyo explains, are dependent on yeast choices. How fast they ferment and their alcohol tolerance dictates how many vats. Do they produce aroma worthy of batch distillation or should you go continuous? It all begins with yeasts.

When I first read the works of Percival Greg in Jamaica and his descriptions of yeast no. 18, I became wildly curious about Schizosaccharomyces Pombe. Pombe is a fission yeast as opposed to a budding yeast so they divide differently. All brewers yeasts are budding yeasts and pretty much no beverage uses Pombe yeast but rum (industrial wineries are exploring Pombe to reduce malic acid because they can metabolize it into alcohol). The name Pombe is Swahili for beer and it was first identified in African millet beers in the late 19th century. It has been explored in conventional beers, but is known to produce off aromas in the context. Not even all rums use Pombe yeasts, but typically those of the grand arôme tradition do (I use that term without nationality because I like the ô). Geneticists have been studying them as a model organism for looking at mutations because of how they divide, so when searching for information you have to wade through a lot of genetic science.

Yeast type seems to be something beverage people have forgotten about and connoisseurs don’t even know to make the distinction. If used properly, Pombe can make the heaviest, most suave of rums, but they can also be used to make straight light rums. Many producers inoculate with them and many other producers accidentally end up with them. Among the serendipitous category, some end up producing a heavy type of rum while most others sort of sabotage their chances of grand arôme by other contingent practices. Typically, producers of heavy rums, are keener on their science and with great care, coax their Pombe yeasts into producing tons of gorgeous aroma.

[Fermentor at Hampden estate in Jamaica, likely a top fermenting Pombe yeast and closely matches the description of Percival Greg’s. Image credit Rum Gallery]

Schizosaccharomyces Pombe yeasts have sub categories just like budding yeasts and there are top fermenting and bottom fermenting varieties. As a rule of thumb top fermenting yeasts produce a fuller bodied aroma and ferment even slower. Pombe yeasts do not produce all the aroma themselves, and the slowness of their ferment means that favorable bacteria can take hold and produce desirable aroma compounds. It also leaves room for undesirable bacteria and Pombe yeasts typically require more care which is why many distilleries avoid them.

Pombe yeasts relate to the dunder process because as a rule of thumb they have significantly more osmotolerance than budding yeasts. This means they can withstand the stress of high acidity, high initial sugar contents, and high contents of dissolved minerals that accumulate in dunder. Jamaica and many other areas likely ended up discovering Pombe yeasts via sloppy fermentation practices where things weren’t measured properly. Empirically it was revealed that dramatically different results could be gotten. There was a time where distillers were just learning about bacteria and how it was inhibited by acidity, so to protect yields they were heavy handed and eventually ended up with a rare yeast type. When acidity is high, Pombe will take hold as the dominant yeast, but bacteria will not and this is a way to get particularly light rums as a result of using Pombe. This idea may have great bearing on older Haitian rums pre-1980’s and many small production Cachaças.

It was initially thought that high acidity correlated to fuller flavored rums but that isn’t exactly true, the Jamaicans were sort of wrong and Arroyo straightened it all out. More on that later, because it gets really profound.

Another point I should make is that fission yeasts relative to budding yeasts have a low frequency of occurrence. That is why they are typically not dominant, but can be made to be dominant as part of a community by messing with fermentation kinetics. The low frequency of occurrence, coupled with being abandoned by the industry, and the rise of in house research by certain sophisticated firms means there are no industrial catalogs of Pombe yeasts to choose from like there is with budding yeasts. There is a Pombe society, but it is a group of geneticists and not a group of rum aficionados.

If you want to mess with fission yeasts, you need to round a bunch up and have them go through a fermentation Olympiad. This is what Jamaican had done very early on and their Agricultural experiment station would send a new yeast out at the beginning of the season. Later in the season they would find that it often wasn’t still dominant. Arroyo conducted his own Olympics with some extra wild results, and the French have held their own games for themselves. Arroyo doesn’t say much on the actual methods of discovery, but he does describe his pentathlon better than anybody.

The big test is the yeast’s ability to produce rum oil, which is the mysterious prized metabolite and something fission yeasts produce more of than budding yeasts. Pombe yeasts have to be found at random (a strategic random), purified, then run through feats of strength. After they pass the rum oil tests, they have to go to the fusel oil event. For grand arôme rums, fusel oil has to be minimized during fermentation because fusel oil and rum oil fractions overlap in the still. If you use a fusel oil separator in a continuous still, or a decanting technique in a batch process, prized rum oil will be lost, so unlike other spirits, rum has to be that much more in tune with its yeasts. You can ferment molasses with yeasts, distill it, and not get rum, (but my God will they try to call it rum!) They will also probably try to adulterate it instead of learning more about fermentation. Rum is that much more profound than other spirits.

I have long wanted to bring fission yeast to New England and I’ve slowly been hatching a plan. My initial plan had to be scrapped as I learned much more. You cannot exactly get a pombe yeast from the catalogs. I mean, you can for $350USD, but it has yet to be vetted and win a gold medal, and it has to compete against a lot of other candidates so ultimately you would need a few thousand dollars just for your first cultures and they’d come with no story. Rum has to have a story, and typically they all do, more so than any other spirit.

I plan on taking a slightly different tack, I am going to do discovery myself, and then hold my own Olympic trials. I will try wide ranging local discovery with various fruits, but it doesn’t look promising (I need to verify that hunch is correct regardless). Isolating budding yeast is easy, but even when understanding their typical kinetics, isolating fission yeast, with their low frequency of occurrence is hard. I have hatched an extra novel plan which would get me a standing ovation with the yeast biologists if I can execute it. I have an extraction protocol with a track record of success and I’ve already been collecting exciting sample media from around the world. Arroyo isolated near all his contestants from sugarcane, but I do not think that is the only way. I’ll have contestants coming from as far away as Sardinia and I have eight potential contestants from within Minnesota alone, that with genetic testing I can give first names to. Will any be the same or will they all be unique? And what will my distribution of tops and bottoms be? Or am I completely wrong and all the gold medal winners must come from sugar cane because they are best adapted? There is only one way to find out! I do have a yeast biologist partner in crime for this so I’m hoping the protocol will be successful.

My initial plan was to understand Pombe kinetics enough to create dominant cultures in varying mediums like apples, raspberries, foraged blueberries, etc very much like what is rumored to happen at Hampden estates. This would also come with free riding bacterial communities. This plan was dashed because though I could possibly construct a starter one way and build a large footing to optimize aroma and fusel oil production. The rest of the wash would be very different and the community would change significantly. An entire community from a starter would bring an elegant sense of terroir, but it would not be correlated to the most extraordinary of sensory values. Until I learn more, my initial best bet is Arroyo style pure culture fermentation.

The majority of the rum industry that found themselves with Pombe yeasts have abandoned the practice and in many cases because it didn’t meet their objectives or technical abilities. For a long time, and for much of the world without any established reputation, rum sold largely on price. Being most competitive required continuous stills which need continuous streams of wash to run. Vats require capital expenditure and to feed the hungry stills, a quick fermenting budding yeast could turn around a vat much faster, thus reducing expense. In many scenarios Pombe yeasts also have less alcohol tolerance than budding yeast which means more energy to separate all the extra water. Arroyo and a few other consultants tell tales of massive distillery wastes due to incomplete fermentations. Pombe yeasts are never singled out as at fault, but these distilleries were never testing the boundaries and limits of their workhorses. Biological control requires chemical control and if you don’t even have that, you just cannot mess with fission yeasts.

We are going to see a fission yeast renaissance. The first step is recognizing their current usage on the market and their usage historically. Did New England rum at Felton & Son’s ever use a fission yeast? They did make very full bodied rums and were using dunder. There is one untapped resource left to possibly find this information (and I’m working on it!). Is Hampden estates using the most noble of grand arôme fission yeast processes? Does Cape Verde end up using a fission yeast? In the previous post I attributed much of their character to cane juice not being defecated or clarified, but if a cachaça producer could end up with a fission yeast, why couldn’t a grogue maker? Answering that question may be as simple as asking how long their fermentation lasts.

The next step is bringing it to the new distillery movement. There are countless new distilleries producing rum but do any of them have progressive yeast labs and is anyone holding systematic trials for their yeasts? (Hint: partner with a university!)

Yeasts we will see are where it all begins, but they guarantee nothing if not followed up with chemical control and more in depth understanding of their specific metabolisms. Next, and after I gather a little more information, we will move down the road and look deeper at comparative fermentation options for rum making.

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Cape Verde and Sugar Cane Juice Rum Categories

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I finally finished Arroyo’s Studies on Rum and thought it was really inspiring (I will upload my copy when I get a chance to optimize the PDF). I aim to give an in depth optimistic and pessimistic review of his work soon, but I’m a bit busy and might build up to it as I do more background research.

One thing that caught my eye towards the end of the book was Arroyo’s explanation of sugar cane juice rum categories that we just don’t seem to recognize anymore. This was the difference between defacated & clarified rums versus raw and pure types. Arroyo was an advocate for clarifying sugar cane juice, observing that it’s rums matured faster, while I am an advocate for the raw state or at least celebrating both. Martinique would be a prime example of a defacated and clarified style while Cape Verde would be an example of the raw style. If these were Chardonnays, Martinique would be something a banker would prize out of California and a Cape Verdean grogue would be something garagiste & cult out of Burgundy.

Let me see if I can find Arroyo’s own language, It starts on page 171 in the chapter on Rum Aroma:

[…], a raw sugar cane juice will produce a raw rum quite different in aromatic tone to that of defecated and clarified juice. The rum produced by the raw sugar cane juice will be much richer in the makeup of its Non-Alcohol-Number than that obtained from the defecated and clarified juice. Hence raw cane juice will tend to produce a “heavy” type of rum, while defecated and clarified cane juice will tend to produce a very light type of rum.

Our experiments dealing with sugar cane juice rums have demonstrated that:

(1) The rums produced from raw cane juice are more aromatic, but the aroma lacks the finesse of those produced from defecated and clarified sugar cane juice. These rums also will take a longer period of ageing to reach maturity. When the organoleptic tests from aroma are applied to a sample of this type of rum, it gives the impression that a blend of various rums rather than a single one is being tested; in a word, the rum aroma lacks stability and uniformity, being also rather pungent.

(2) The rums obtained from pasteurized sugar cane juices, but not clarified, occupy an intermediate position with respect to the quality of the aromatic gama. Their aroma is more uniform, stable, suave and delicate. It possesses a more harmonious blend of the different components. Complexity of aroma may be present, but it is stable; and presents a single aromatic effect.

(3) The rums produced from the defecated and clarified sugar cane juice have the same general characteristics as those produced in the same case of pasteurized cane juice; but they possess, besides, greater amplitude and penetration of aroma. Certain tinge of the peculiar odor of matured rums may also be observed in the bouquet of these particular products.

The natural aromatic constituents present in the raw materials used will become another important factor in the bouquet of the resulting rum. In this particular we have that different varieties of sugar cane yield juices with different classes and amounts of aroma. Also in a given cane variety, the aromatic tone will differ according to state of maturity, time elapsed between cutting and grinding the cane, whether burned or fresh cane is cut and ground, etc. etc.

Wow. What beautiful language and he never says that word balanced that I abhor. You can sense Arroyo really grapples with language to meet you on the same plane of experience. He gives us uniformity, which is the language of space, stability which is temporal, suavity which is more abstract, cultural, and definitely reflecting his Spanish stance (#phenomenology). There is harmony, amplitude, and tone which are most commonly the language of sound and music. Arroyo uses tinge which refers to a grappling with scale (remember my obsessions with the scaler adjective problem?). Arroyo’s language is really refreshing and a lot of my first collecting projects were to look for evidence of unique language used by producers to convey sensory experiences.

I identify with this Arroyo guy because he is also tuned into metaphor in a way others aren’t yet. In a few paragraphs he also shows us we know near nothing about rum. All the rum talk of the recent renaissance is bunk (but hopefully that is liberating and leaves you optimistic).

Arroyo’s words also defy my Chardonnay analogy and sort of challenge notions of manipulation relative to terroir, but I am standing my ground as an advocate for Cape Verde as producer of the greatest fresh sugar cane juice rums of the world. I originally saw that pungency as a sense of place, though now I know it is mostly a matter of technique (though it is likely the last place to use the technique!). I even speculated that it may have gotten there by not fermenting the beers to dryness and thus getting an exaggerated ratio of aroma to alcohol (a la mosto verde Pisco), but now I know I was wrong. Whatever it was, it’s low frequency of occurrence among the rums of the world really captured my attention.

But those aromas, that lack of uniformity, and over the top pungency take on rich cultural symbolism. It is all very similar conceptually to Mezcal. It is hearty like a home cooked meal and so often that beats carefully composed restaurant food. There are no regrets or missed opportunities in the heads & tales cuts, but those aromas are wild. We could also find a word that would be in the same category of suavity, but it would mean something quite different. I bet the Cape Verdean dialect of Portuguese has a word readily available, you probably use your hands as you say it.

Cape Verdean life is no picnic and hard work is done by hand infusing itself into the spirit. The cane is crushed by hand power with a trapiche. The music of Cape Verde, the mornas, popularized by Cesária Evora, originally moved to the slow beat of the trapiche. This poor country where everybody lends a hand pushing the trapiche has no continuous super centrifuge of Arroyo. The fires of the still are tended to by hand, fueled by cane bagasse and the temperature is maintained by intuition coupled with watching the flow out of the wooden condenser.

Romance is wonderful, but some of these spirits can slum it a little too much and wind up with taint from copper corrosion due to not nearly enough condensing power or the lack of stainless steel that much of the distilling world has gravitated towards for condensers to reduce ethyl carbamate as well as copper salts. University research papers that cover grogue, and draw comparisons to Cachaca, pretty much only dwell on condensing issues related to quality.

Not all of Cape Verdean production is so rustic and I suspect some of the rums that I love the best, such as Vale d’Paul and Joao Monteiro, are produced in facilities that are relatively more modern. As I checked for spelling, I found some vintage egullet talk on the grogue subject worth browsing.

Not everyone quickly regards the Cape Verdean rums like I do, but how does that change as you’ve come to appreciate Mezcal or learned how it is fermented in the truly raw state unlike the centrifuged, clarified and defecated spirits of Martinique?

Cape Verde still has a lore that much of the rum world has come to lack (on its surface). There never was a sugar cane industry in Cape Verde. Sugar Cane was a failed experiment and became a backyard crop which has to be grown with extreme sensitivity because of the desertification that afflicts much of Cape Verdean agriculture. Rum production goes back centuries but it was completely illegal for much of that time and thus could be seen as the greatest moonshining tradition of the world (second only to the Medronhos of the Al Garve).

The last time I sat down to talk grogue with a producer’s son, I was told of an amazing heritage. The head distiller of Vale d’Paul is in his nineties and has distilled his entire life. He has even recognized plots within his own property that produce the best cane for rum making and he sets them aside for himself. At the end of this recent post, there was a telling of terroir recognition among Sri Lankan Arracks, and it no doubt also exists in cane juice rums though we as imbibers have not matured enough to create a demand for it. I’m dying to taste those single plots of Vale d’Paul.

Should we launch a kick starter to buy Cape Verde some Swiss Alfa Laval continuous centrifuges or should we embrace them as they are and hear their story of undisrupted rum production?

Is Cape Verde the living link to rum production of the 19th and early 20th century?

New non-molasses producers are entering the fray, but do they truly know how to sculpt rum? (I am always for sale by the way, and I’m still keeping a lot of secrets from you all.)

We have a long way to go and a lot to see, I have a feeling drinking rum will keep getting better and better.

[Where do we go next? Astute reader, David Wondrich, was quick to point out that many Brazilian cachaças are produced unfiltered & defecated yet do not have defining characteristics found in Cape Verdean rums. So how do we explain that? It has long perplexed me that cachaças don’t share more characteristics in common with Martinique rhums and I’m just beginning to find explanations for that as well.

If we backtrack to Arroyo for a minute:

Also in a given cane variety, the aromatic tone will differ according to state of maturity, time elapsed between cutting and grinding the cane, whether burned or fresh cane is cut and ground, etc. etc.

Some of these ideas are relevant and of course we know they matter in theory, but what we don’t know is the very specifics of how things differ practice. We also latch on to ideas like cane variety or the type of still used and too often ignore specifics of fermentation yet I suspect that is where the most salient aspects of differentiation come into play. I’d like to think I’m well versed in fermentation and most importantly, comparative fermentation, but I’ve put off writing about it for quite some time. Slowly I’ll tackle fermentation options. I’m itching to tackle some yeast and bacteria topics, but I’m waiting for consulting project to materialize a little further.]

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