Beyond The Barrel: Facts About Whiskey Barrels & Other Aging Methods

What makes whiskey, whiskey? At its core, whiskey is just a mash of fermented grains (usually barley, rye, corn, wheat or a combination of these) that is then distilled & aged in wooden barrels. The barrels are typically made of white oak, which after several years of aging, ultimately gives whiskey its color & flavor. In fact, if it wasn’t for the process of aging the spirit in wood barrels, whiskey would be clear & taste more like vodka than the traditional whiskey taste we all know. So, it’s the barrel that ultimately makes whiskey, whiskey.

For hundreds of years, white oak has typically been chosen to make whiskey barrels because of its watertight properties. The wood holds the spirit in, allowing it to slowly age over a number of years as the flavors & color from the white oak barrel infuse into the spirit. When it is taken out of the barrel (our whiskeys typically age for 3.5 to 4 years), the spirit emerges with a rich, dark color & smooth, oaky flavor, typically with a minimum ABV of 40%. The type of wood used in the barrel, as well as the length of aging & whether or not the barrel was previously used, impact the flavor profile of the whiskey significantly. And once the whiskey is taken out of the barrel, it stops aging, leaving behind the rich colors & flavors imparted by the barrel.

Now while it is tradition, the decision to use white oak barrels to age whiskey was simply a practical one - distillers liked the fact that white oak makes the barrels watertight. This tried & true method has been used by distillers across the globe for hundreds of years, and in fact, Split Spirits uses white oak barrels to this day to age our Ridgeline Vermont Whiskey, Barred Owl Bourbon, Drumlin Champlain Valley Rye & Essential Vermont Malt Whiskey. But because the same type of wood has been used to make whiskey barrels for hundreds of years, we have been limited to the flavors that come from white oak barrels. There are over 1,000 of species of trees that grow across North America, so that leaves you to wonder, what other flavors are out there?

When Split Spirits was founded in 2019, our founder, Will Drucker, began to toil with that question. What other types of wood could be used to age whiskey, and what different flavors could be captured in the bottle? Will began to experiment with different types of wood, including sugar maple & black cherry, to age his spirits. But he quickly noticed a problem - sugar maple & black cherry wood are not watertight. While it did create interesting new flavors, neither wood could be used to make a barrel because the whiskey would seep through the wood. That brought Will to a new question - what if we abandoned the traditional barrel aging techniques for an all-new process? The result: inverse barrel aging.

Inverse barrel aging is a process that ages whiskey from the inside-out, rather than the outside-in. In traditional barrel aging, the flavors from the wood infuse with the spirit as it sits in the barrel for multiple years. As the spirit sits surrounded by the watertight white oak, the flavors & colors from the wood seep into the spirit, creating whiskey. Inverse barrel aging, on the other hand, does not use a barrel at all. Rather, the spirit ages in a drum with splits of wood dropped into the middle, allowing the flavors & colors from the wood to infuse with the spirit from the inside-out. By not using a barrel, we create a smaller surface area for the spirit to age in, so it actually requires less time to age spirits than traditional barrel aging.

Inverse barrel aging also allows us to use different types of wood that are not necessarily watertight, including sugar maple and black cherry, as well as parts of the tree that are typically thought of as “unusable” to make whiskey barrels. Using different types of wood allows us to capture flavors that you can’t get from white oak, and using unusable parts of trees follows sustainable forestry practices, which is at the core of Split Spirits’ mission.

Now because inverse barrel aging uses splits of wood to age the spirit & not wood barrels, we technically can’t call it whiskey, hence the name Split Spirits. While the majority of our whiskeys are aged using traditional barrel aging methods, the three spirits that make up our Split Spirits Collection - Vermont, New York & Illinois - are aged using inverse barrel aging. Once aged to maturity, the spirit is bottled with a charred split of either sugar maple, black cherry or white oak wood dropped directly into the bottle, so the spirit continues to age from the inside-out as it sits in the bottle.

The splits of wood found in every bottle of Split Spirits are harvested from the unusable parts of trees that have already been felled, following sustainable forestry practices. The sugar maple wood found in Split Spirits Vermont is harvested right here in the state of Vermont, while the black cherry wood is harvested in New York & the white oak is harvested in Illinois, so there is quite literally a piece of the place where the spirit comes from right in the bottle. That’s why at Split Spirits we make “Sustainable Spirits With A Sense Of Place.”

So whether we’re using inverse barrel aging or the traditional method, the result is always the same at Split Spirits - fine, handcrafted, sustainably made spirits that foster a sense of community, adventure & connection to the land. We are constantly experimenting with different types of wood to create new flavors in our spirits, while still embracing the traditional barrel aging methods that have worked for centuries.

Visit our distillery & tasting room in Middlebury, Vermont to learn more about how we age our whiskeys & try our entire line up of fine craft spirits. We are also selling a number of our used whiskey barrels from our distillery to make room for new production runs. If you own a bar, restaurant, brewery, winery or event space, or you want an authentic Split Spirits whiskey barrel to spice up your home, please contact george@splitspirits.com.