A few weeks ago, I discussed the topic of blended whiskies. I mentioned then that nearly all whiskies are blends, even single malts, in the sense that they're a mixture of whiskies from one single distillery. I have a few last comments to make on whiskey blending, and then I'll be done with this topic for a while. We've been talking about scotch up to now, but I'll be illustrating my point today by looking at a project from a bourbon distillery.
The folks at Buffalo Trace have been experimenting with an interesting project, and I've been following it for some time now. Called the Single Oak Project, it's a pretty ambitious idea: take seven variables that can affect the flavor of a bourbon, tweak each of those variables, release a range of bourbon styles to the market, and let consumers vote on their favorites. Here's how it works.
In 1999, BT's warehouse manager traveled from Kentucky to the Missouri Ozarks to hand pick 96 trees, made of wood of varying grains—fine, medium, or coarse. Each type of grain, in theory, leads to a different flavor profile. (Grain size is the first variable.)
Each tree was cut into two sections, top and bottom (the second variable); carved into barrel staves; and air-dried—some sections for six months, some for a year (variable #3). BT then experimented with char levels, toasting one half of the barrels for a little longer than the other half (variable #4).
BT filled those barrels with two different recipes of bourbon (the fifth variable). In one recipe, the secondary ingredient (after corn) was wheat; in the other, it was rye. To further complicate things, some barrels were filled with 105 proof bourbon and others with 125 proof (variable #6).
Finally, the seventh variable was the aging warehouse where the barrels were stored, and this is what we'll specifically discuss today. Two different warehouses were used. In one warehouse, the barrels were aged while resting on wood; in the other, the barrels aged while resting on concrete.
Seven variables are at play here, and any of them can, in theory, affect the flavor of the finished product. What BT is experimenting with is to what extent consumers can taste the difference, and what factors consumers prefer in their bourbon.
BT aged everything for eight years, and now they're slowly releasing bottles from each of the 192 barrels. Each bottle, of course, is a single-barrel release, unblended with bourbon from other casks, so the unique characteristics of each cask, theoretically anyway, shine through. For whiskey collectors and bourbon geeks, this is pretty heady stuff.
With each release of the Single Oak Project, Buffalo Trace issues a set of twelve bottles. In the latest release, two of those twelve bottles have only one variable that differs: the warehouse. Everything else about the two whiskeys is identical: the recipe, the proof level, the level of char in the barrel, the grain of the original wood, and so on.
Warehousing may seem really mundane, but I bring it up here to raise a point. The whiskey writer Chuck Cowdery discussed this project on his blog in early February, and he quoted Buffalo Trace's master distiller:
[A]ging barrels in different environments affects the taste of the whiskey. There has always been much discussion about warehouse placement, even among ourselves, so we're anxious to hear how others rate these bourbons.
The point I'm raising is that even something so seemingly mundane as warehouse placement can affect the flavor and character of a whiskey, whether that's bourbon, Scotch, or Irish. For that matter, warehousing can affect other aged spirits, as well—rum, brandy, tequila, etc. Barrels are moved from floor to floor of a warehouse during the aging process, to ensure consistent aging, but in a large operation like BT's, even the warehouse itself can affect the product.
So this is just one concrete (pardon the pun) example of why blending is such an important part of whiskey production. The number of variables that can affect the flavor and character of a single barrel of whiskey is larger than most consumers can imagine. The best way to ensure consistency across releases is to have a master blender who can taste each barrel as it becomes ready for bottling and blend it with other barrels in the warehouse to ensure a consistent product. I've used Buffalo Trace bourbon as an example here because the Single Oak Project is such an ambitious and interesting endeavor, but it's true of any aged spirit, especially whisk(e)y.