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.