While location, location, and location, are the three factors traditionally used to distinguish among single malt Scotches, such factors just don’t apply when it comes to straight Kentucky bourbons. Though a single malt Scotch is always described by its specific area, down in the Bluegrass State, it just ain’t so. The nine Kentucky distilleries that make bourbon rely on some incredibly fine-tuned, fairly modern equipment working in tandem with some true-blue American whiskey-making traditions that have been passed down for, in some instances, over 200 years, in order to make their whiskey’s different styles sing.
Many spirit aficionados will raise an eyebrow when they realize that bourbon goes through its primary distillation in a continuous still–something that would never happen in a Scottish malt whiskey distillery, where the less-efficient pot still, renowned for producing highly flavored spirits, is the only type of alembic used. However, I have seen such eyebrows swiftly relaxed when Scots learn just how their Kentucky counterparts use their equipment. The exact processes can be rather complicated, but if you bear in mind that American whiskeymakers have been tinkering with continuous stills for well over a century, you come to understand that these guys know their equipment like Keith Richards knows his fretboard–they understand every last nuance of their stills. At the bottom of one such still lies a wrench, left there decades ago by a maintenance man. No one dares touch it lest it changes the whiskey that the still produces.
The factors that differentiate the bourbon from one distillery from the next one are many: The water source is a prime factor, as is the mashbill (the grain recipe that denotes the percentage of each grain) and the differing amounts of setback (sour mash) added. Some distillers use a doubler (a type of pot still) for their secondary distillation while others choose a thumper (a different type of pot still), and various other intricacies are employed by each and every master distiller in Kentucky to make sure that their particular whiskey is distinctive in its own right. One of the most fascinating aspects of bourbon-making, however, occurs in the small white-washed rooms where yeast, the lifeblood of every bourbon, is cultivated. They are known as “dona” rooms, and they are somewhat sacred among the distillers who use them.
Up a few rickety wooden stairs at the Heaven Hill distillery in Bardstown, Kentucky lies a dona room where Earl Beam (Jim Beam’s nephew) used to celebrate “jug yeast day” (the day on which the yeast is cultivated) by cooking a “fry-up” for himself and his helper. He may not have realized how significant his ritual was, but some primordial force drove Earl to reward himself with food on the day that he nurtured his yeast. These days, Earl’s son and grandson, Parker and Craig, still cultivate the yeast in that same room, and although they don’t cook lunch in there, they understand that the space is hallowed ground. When I visited the distillery with my wife last year, we were told in no uncertain terms that not many people are allowed into the dona room.
Six distilleries in Kentucky–Maker’s Mark, Early Times, Wild Turkey, Heaven Hill, Jim Beam, and Four Roses–have dona rooms; the others prefer to use specific strains of dried yeast. And although the “dried yeast” distilleries produce distinctive whiskeys in their own right, nothing can compare with the romance of the dona room where master distillers perform intricate procedures to keep their yeast strains alive, feeding it with various grains and adding a pinch of this and a teaspoon of that in order that their particular whiskey remains true to its roots.
There’s a ritual of sorts to the procedures carried out in dona rooms that even the distillers themselves don’t fully understand: each one knows exactly how to propagate their yeast in order that their whiskey will be absolutely consistent, and each one knows exactly what the end product should be, but most carry on this process, step by step, week after week, simply because “that’s the way my Daddy used to do it.” Even the word “dona” isn’t fully understood, although Ed Foote, master distiller at United Distillers’ Bernheim plant, suggests that the word could be tied to the Latin root donna, meaning “mother.” It’s certainly the best explanation I have heard since the distillers are, in fact, “mothering” their yeasts–feeding, nurturing, and watching them grow. But what actually happens in these hallowed rooms? And how does what they do affect the whiskey we drink? We’ll start out by looking at how Steve Nally, master distiller at Maker’s Mark, cultivates his particular yeast strain.
According to Bill Samuels, Jr., president of Maker’s Mark, the yeast strain used at Maker’s was saved by his father and kept alive during prohibition to be used again when the Samuels family re-fired their stills in 1933. Every bourbon man knows that his yeast strain must survive at any cost. Nally keeps his “jug yeast” refrigerated, in a covered brass vessel where it lays dormant in a solution of liquid malt, and come jug yeast day he removes a portion of the yeast mixture and starts the process of multiplying the yeast cells.
To accomplish this, Nally must literally “feed” the yeast: First, he heats some liquid malt in his dona tub, a double-walled container that can be heated or cooled by the introduction of steam or hot water to the tub’s “jacket.” While the malt is cooking, he throws some hops in there. That’s right–hops. How this practice began is somewhat of a mystery, but it’s possible that hops were initially used to ward off harmful bacteria. These days, however, they are used to add certain nuances to the whiskey. (For the record, hops are used by Maker’s Mark, Heaven Hill, and Jim Beam; the alternative, sour yeast mashes, are used by Early Times, Four Roses, and Wild Turkey. Seemingly, if hops are used, the mash shouldn’t be soured.) When the malt has extracted some hop flavors, the yeast is added and the mixture is allowed to stand at room temperature for about 24 hours (actually, the mixture is cooled occasionally since the yeast creates heat as it multiplies and the idea is to maintain a somewhat constant temperature).
Meanwhile, Nally prepares his “day yeast,” quite simply a “porridge” of cooked grains, in this case, malted barley and wheat. (Terms can get rather confusing, some distillers call Nally’s “day yeast” a “yeast mash.”) Most other distilleries use rye as opposed to wheat, but at Maker’s Mark, they prefer the somewhat subtler flavors of wheat to produce their bourbon (the only other “wheated” brands–W.L. Weller, Old Fitzgerald, Rebel Yell, and Kentucky Tavern–come from the Bernheim Distillery in Louisville). Next, Nally transfers the yeast, which has doubled in quantity every two to three hours, from the dona tub to the larger vessel that contains his day yeast. He leaves it there for around three hours to give it a chance to multiply one more time in its new environment. After this period, the yeast mixture is ready to use. It is added to the fermenter where a cooked mash of corn, wheat, and malted barley awaits. In three to four days time, the new mixture, the “distiller’s beer,” will be distilled to make the whiskey. There now, that wasn’t too difficult was it? But what about those hops–do they really make a difference to the whiskey?
If you listen to Lincoln Henderson, master distiller at the Early Times distillery in Louisville, the hops do matter–a great deal. Henderson makes Early Times bourbon (available for export only) as well as Old Forester bourbon, and all the whiskeys he makes use a jug yeast cultivated in a dona tub. At one point Henderson experimented with hops in his yeast mash, and he swears that the whiskey it produced was totally different from his regular style. He stopped the hops experiment immediately; consistency of product is vital to the whiskey business. Was adding the hops a bad thing? No, but it just didn’t work for Henderson. The fact is that each distillery is merely producing their particular style of whiskey, and any alteration in their procedures changes that style. Similarly, if a distillery that uses dried yeast switched to a jug yeast, chances are they’d have a whole new whiskey.
At Early Times, Henderson uses a “sour yeast mash” to cultivate his yeast strain, and he does that by adding lactic bacteria to his yeast mash–it’s a similar method to that used by Ova Haney, master distiller at the Four Roses distillery (another bourbon available only in the export market). Jimmy Russell, however, keeper of the stills at the Wild Turkey plant, sours his yeast mash by holding it at a constant temperature for about 22 hours, popping in to stir it every three hours or so. Once again, we see different methods–largely similar but with small differences–yet each produces a distinctive style of bourbon.
On the technical side of these procedures, each distiller works overtime to produce and maintain an environment that is perfect for its particular strain of yeast. The pH levels are key, and by varying their yeast mashes (as well as by the addition of setback), this level can be lowered to the desired point. Yeast enjoys more acidity than is usually produced by merely cooking the grains, although too much acidity is just as harmful to the organism as too little. It’s the “three bears syndrome”–everyone is out to get it “just right.” And they all have their own way of accomplishing their goal for their specific strain of yeast.
While it would be impossible to sift your way through every nuance used in the making of Kentucky bourbon to discover which methods work “best,” it does pay to look at the care that goes into making each one. The best bourbon you ever taste could be from any one of Kentucky’s nine distilleries–it’s totally subjective, a matter of personal preference. Nevertheless, it is interesting to discover who does what at various stages of production, and the “dona” process, to my mind, is one of the more interesting arts of the American whiskey distiller. So, next time you find yourself savoring a drop of red liquor from Kentucky, spare a thought for the traditions of American whiskey–it’s one of the very few spirits that can be traced back to its origins. Bourbon’s heritage, like most American institutions, is one of tradition and progress, and although those two “factions” are locked in a constant struggle for dominance, the result is purely American.