Roll out the barrel: The aging process, unpacked

When you think of whiskey, you likely picture its rich brown color and complex flavors. But freshly distilled, unaged whiskey (also known as “white dog”) is as clear as vodka. And much like vodka, unaged whiskey doesn’t have much of a personality. It tastes and smells just like the ingredients in the mash bill. So where does whiskey get its personality? Almost entirely from where it grew up — the barrel, where it lives for anywhere from two to 30 years.

But we should clarify that the elements of the environment around the barrel can impact the flavor as much as the barrel itself. In fact, our friends at Catoctin Creek Distilling would argue their rich Virginia terroir is equally important to their finished product. As the barrel expands in warm temperatures, whiskey is pulled into the staves, filtering through the charred wood. As the barrels cool in the winter, the whiskey is forced back out and brings with it some of the characteristics, flavors, and oils of the barrel. What was once a clear, fairly boring liquid becomes a vibrant amber hue with all of the rich flavors we love in our whiskeys.

However, all that flavor and complexity of the aging whiskey comes at a price. Each year, around 2% of the whiskey inside the barrel is lost to evaporation. This is affectionately called the “angel’s share.” That may not seem like a lot, but over time it adds up. Depending on the length of the aging process, a barrel can lose as much as 40% of its contents to those pesky angels. And as you might imagine, warmer climates such as Kentucky and Tennessee have thirstier angels than more temperate climates such as Scotland or the Pacific Northwest. 

One of my favorite things about the aging process is how different each barrel, even if they all started with identical distillate from the initial cook, may turn out. Like snowflakes, no two wood staves are 100% identical, and things as seemingly insignificant as cell structure and rainfall can ultimately impact what flavors the wood will impart on your whiskey. This is something the gentlemen at Locke + Co discovered when they started cutting their Aspen discs crosswise instead of lengthwise. Some barrels wind up with extremely distinct flavors — and may be labeled as a “chocolate,” “caramel,” or even a “grapefruit IPA” barrel (one of Carter Collins at Pennington Distillery’s favorite distinctions). These barrels typically are labeled and blended together in precise ratios to create a consistent flavor profile, even among small batches.

But every now and then, the true “A” student comes along — with all of the complexity and depth of flavor packed into one individual barrel. These barrels are usually set aside and presented to the world as “single barrel” offerings, gems of the whiskey universe where no two are ever exactly alike. It’s worth noting that single barrel offerings aren’t necessarily “better” — often they’re even hit-or-miss. But when they hit, they have a tendency to be absolute home runs.

Whether you prefer the gamble of a single barrel or the more consistent flavor profile of a blended small batch, so long as you’re running with the Barrel Outfit, you’ll always be getting the best the great distillers across this country have to offer.