The Revenue Men Explain Natural-Fermentation Sour-Mashing

“Jug to Dona, Dona to Yeast Mash, Yeast Mash To Fermenter” (How We Got There)

– Quotation from Bulletin Relative To Distilled Spirits, 1912

In 1912, the U.S. Bureau of Internal Revenue released its Bulletin Relative To Distilled Spirits. The introduction, by Commissioner Royal Cabell, expresses succinctly and clearly the object: to guide internal-revenue officers whose work brought them in the purview of distilleries. The text itself is as clear as one could hope for, intended for the educated general reader without requiring too much theory.

Scientific books, and books or journals written for the trade such as Bonfort’s Wine and Spirit Circular (of which earlier-mentioned Thomas M. Gilmore was publisher, incidentally), inevitably cover topics only partially or from the writer’s perspective. They are most valuable if one reads enough of them – indeed there is no substitute for it – but sometimes you run into an authoritative summary, which is the Bulletin mentioned. You can’t hide from the government…

I append below a page from the Bulletin, which summarizes yeasting practice in distilleries in 1912. There were three types: the small tub one I have been elucidating in recent posts, where the mash ferments naturally without addition of any yeast (small tubs held about 50 gallons); fermentation in a large vessel (as today) where yeast was collected from a previous ferment and dumped in. This was often called yeasting-back and the form of yeast, barm; and the most modern method, where a selected yeast is grown in a special grain mash, stored in a metal dona and then cultured in a large quantity as needed to seed the next production. The last is today’s system except we also now have distiller’s dried yeast as an option.

As can be seen, the method of E.H. Taylor and Dr. James Crow, recorded by Internal Revenue in 1912, was on its last legs. The reason was inefficiency again, both the conversion from starch to sugar and the latter to alcohol could not compete in output and quality with the third system. The second system was middling in results, relying on an ever-diminishing yeast capability as the generations progressed and incurring a higher risk of bacterial contamination than method #3.

A different source from about the same period, when mentioning that backset is used to scald the mash for sour-mash whiskeys, stated that the “original” method was actually to use water. At first this surprised me, but when you think about it, farm-distillers would not have distilled continuously. Distilling would have been intermittent. They therefore would not have had a regular supply of backset from stilling to add to their new mashes. Therefore, they needed barm, which they made themselves from scratch or obtained from the lees of brewing or wine-making.

They may have used backset occasionally, out of expedient or for some other reason, which is why Oscar Pepper may have heard, perhaps in some mountain town or from an oldster, that you could make fine whiskey without yeast if you used backset to heat the mash. Enter the peripatetic Scottish physician, James Crow. His intervention is crucial here. Pepper was an operating commercial distillery, since 1776*. It had a steady supply of backset. Crow may well have been the first to adopt the use of backset and natural fermentation in an industrial setting. When it is said that James Crow perfected the use of sour mashing in whiskey, this in fact may have been his achievement. For this reason perhaps, the Bulletin calls the second or yeasting-back method, “old time”, not the one which relies solely on wild yeast, Crow’s method developed at Oscar Pepper Distillery before the Civil War.

Many other distilleries adopted the practice though which found its greatest proponent in Col. E.H. Taylor but it finally foundered in the first decade of the 1900s. The advent of modern science including the development of pure yeast cultures did it in.

Where are we today? Backset is still used, to acidify the mash mainly. I believe its dead yeast cells furnish additional nutrient. What about its bacteria count, to assist to produce some extra alcohol or (as one distiller told me) fruity esters from consuming the grain sugars? This may be part of the system today unless the backset is pasteurized first. I know Canadian distillers pasteurize backset where it is used, but I’m not sure if Kentucky or Tennessee does.

Of course today there is no yeasting-back much less any natural fermentation. What we have today is a blend of the old sweet mash and sour mash systems, more the former I’d say.

As Col. Tom Gilmore – he was a Kentucky Colonel too – noted in 1896 in J. Stoddard Johnston’s book I’ve mentioned, distilleries operated in different ways. Sour-mashing had variants and in some “fresh yeast” was added, as today, but not in others (read the full whiskey chapter which I’ve linked a number of times). The method which Col. Taylor promoted relied on natural fermentation, as Crow’s system did. That part has been completely lost in American distilling and even yeasting-back has unless a craft distiller is doing it somewhere.

Did it make for better-tasting whiskey? I think it probably did. I think the bacterial component produced special aromas which must have been estery and variously so, those E.H. Taylor with biz org hat on riffed as “tempting the gods”. Bacteria in dunder in pot still rum production produces a similar effect. Modern bourbon isn’t really strongly fruity, but it was at one time, some of it.  By the way, want to know why Kentucky distilling had, and some distillers still follow, two production seasons, Spring and Fall? Because those seasons favoured maximum results from airborne spores and microflora. It reflects a time when small tub natural yeast production became established in hundreds of small plants in Kentucky and Tennessee in the mid-1800s.

*Note added June 15, 2016: This date is probably too early, and there are contradictory statements when Elijah Pepper started to distill. It is known that Oscar his son built a distillery in the 1830s at which James Crow later worked. My interest is not with Pepper distilling family history as such but with the form of small tub sour mashing which relies on wild yeast solely to effect fermentation.