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.

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