It’s not only the compounds found in oak—such as hemicellulose, lignin, lactone, and tannin—that lend flavor to spirits that age in wooden vessels. The previous life of that vessel can have a say, too—and by selecting the right finishing barrel, distillers can add some final layers of complexity to their products.
Going beyond the tried-and-true barrel-aging playbook, many distillers are experimenting with unusual cask finishes to create truly unique spirits.
This shift toward heightened experimentation is epitomized in a 2019 amendment to the United Kingdom’s Technical File on Scotch Whisky. Previously, producers could only mature or finish scotch in a small range of cask types historically used in the industry, such as bourbon, rum, and sherry barrels. However, thanks to changes that relaxed the restrictions, scotch can now age in barrels previously used for other spirits, such as mezcal and tequila.
As craft distilling grows, meanwhile, it can be increasingly challenging to come up with unique, distinct products. For some distillers, selecting unusual casks for additional aging is the secret sauce. It’s an endeavor that’s not without risks—but when it works out, the results can be magical.
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A Learning Curve
When Seattle’s Copperworks Distilling first launched a barrel-aged gin series, the initial idea was to learn about how different barrels contribute flavors to their other spirits.
“We thought we were going to use that to inform whiskey,” says president and cofounder Jason Parker. Instead, the focus on the gin intensified; they discovered that gin botanicals blend especially well with the flavors imparted from casks.
At the beginning, the process of obtaining the barrels was more reactive than proactive. Parker was happy to accept the barrels as and when they were offered. “We never turned anything away,” Parker says. “Our challenge to [ourselves] was, ‘Let’s see if we can ruin a batch of gin.’”
In that, they have failed—they haven’t had to dump a single batch.
However, obtaining the right finish takes time—sometimes much longer than expected, Parker says, for the desirable flavors to develop. Typically, the Copperworks team tastes the spirits once per month to see how the flavors are changing. In one case, however—with gin that was aging in a 600-liter brandy butt—it had changed little during the first two years. After the third year, the team decided to dump it, but then things got hectic at the distillery, and time was too short to make it a priority. When Parker tasted it again after three and a half years, he got a pleasant surprise: It was becoming more interesting. At four years, they bottled the gin, ultimately making for a happy ending for the experiment. However, given how long it took, it’s not an experience that Parker is keen to repeat.
Another issue that Copperworks has faced is dealing with barrels in bad condition. Notably, plans for a tequila-cask gin required a rethink when the barrel, which had probably been dry for about six months, began to leak. “We had to transfer the gin out of the tequila cask,” Parker says, and they moved it to whiskey barrels instead.
Craft-Beverage Partnerships
Instead of accepting used barrels whenever you can get them, you can take a more intentional approach: Decide on a particular type of barrel, and then try to source it from an appropriate producer.
On the Isle of Arran, off Scotland’s western coast, Arran Whisky tried lots of different cask finishes before settling on something specific that the team felt complemented their spirit perfectly, rather than overpowering it. Finding that perfect match can take time.
“Over the years, we were able to narrow down the cask types that worked best with Arran spirit,” says marketing manager Jaclyn McKie, “and gradually we worked to reduce the number of different expressions down and focus on a core range of wine finishes.”
One such is Amarone. “We first released a small single-cask Amarone Wine Cask Finish in 2006, and it became obvious straight away that the profile of this elegant, full-bodied Italian red wine was a good marriage with our Arran spirit,” McKie says.
Forging strong relationships was critical to securing a steady, regular supply of these casks from Amarone producers in Italy’s Veneto region. “We were introduced to a supplier through our Italian distributor in the very early days of our experimentation with different types of casks,” McKie says, “and we have kept this working relationship over all these years.”
At Copperworks, meanwhile, their cask-finishing program has evolved to the point where the team is actively seeking out barrels with particular stories to tell, in contrast to their earlier, more reactive approach. The many craft breweries and wineries in Washington state provide ample opportunities for collaboration. Parker says that he will sometimes put a quarter-ounce of gin into a glass of a local brewery’s beer; the idea is to ascertain how the profiles might clash with—or, ideally, complement—one another.
A particularly successful experiment, now on its 11th release, is their tonic-cask gin. The barrels used in this program have traveled a particularly diverse journey through the beverage industry. For example: What began as a barrel for Heaven Hill bourbon in Kentucky then came to Washington, so that a local distillery could age gin in it; next it went to another local producer, Bradley’s Kina Tonic, which used it to age its tonic syrup; then, Copperworks used that tonic-infused cask to finish their gin; finally, the cask went to Elysian Brewing, which used it age some of its Avatar Jasmine IPA.
Recently, Copperworks also has produced gins finished in casks that previously held strong ales, Adam and Matt, from the now closed Hair of the Dog brewery in Portland, Oregon.
Portland’s Bull Run Distillery, meanwhile, is producing an aged vodka that is a nod to history, at the same time spearheading a local initiative involving other distillers. Dating to 15th century Poland, starka is traditionally a rye spirit aged in wine barrels for many years—sometimes from when a child is born until they are married.
Bull Run distiller Lee Medoff was familiar with Polish, Russian, and Baltic versions; he says he wanted to produce a spirit inspired by that tradition without copying the exact process.
“Although we have an abundance of used American oak barrels, their profile would dominate the flavor,” Medoff says. Instead, he selected French oak barrels that had been used to age Oregon pinot noir, getting a more subtle vanillin contribution. He also enlisted two other local distilleries to make their own versions of starka for simultaneous release, in a collaborative effort called the Oregon Starka Project.
Thanks to a positive response, Medoff continues to make starka. “We now have barrels going back almost 10 years,” he says.
![](https://www.datocms-assets.com/105001/1709579607-absinthe-aged-peerless-rye.jpg?auto=format&w=1300&fit=max)
Photo: Courtesy Kentucky Peerless Distilling
Crafted for Cocktails
Louisville’s Kentucky Peerless Distilling makes a whiskey that works especially well in a Sazerac—because it’s been aged in absinthe barrels sourced from nearby Copper & Kings.
John Wadell, Peerless Distilling’s single-barrel curator and cocktail specialist, says the distillery put lots of thought into the collaboration. “It was important to work with someone whose values aligned with Peerless,” he says. “This crossover is the perfect example of what a few artisans with big ambitions can accomplish when they come together.”
Each absinthe barrel–aged batch of rye has received its own unique treatment. “We age everything based on taste,” Wadell says. The aim is the perfect contrast of notes that allow both the rye and absinthe to be appreciated.
Interesting barrel finishes might require slightly different approaches to marketing. Jennifer Kadell, director of operations at Bull Run, says she believes the distillery’s Medoyeff Starka has a versality because it straddles beverage categories.
“It was once reviewed as ‘a vodka lovers’ whiskey and a whiskey lovers’ vodka,’ and I have never forgotten that tagline,” she says, adding that it works especially well in cocktails. “Our staff has put it in Bloody Marys, dirty martinis, and old fashioneds,” she says.
Appropriate serving suggestions should help consumers better appreciate spirits with interesting cask finishes. Gin finished in characterful casks should be approached more like a whiskey, Parker says, and Copperworks bottles gin at 100 proof.
“The gin holds all of the character that a bourbon or a rye would hold … but it also has spices that the botanicals bring through,” he says. He suggests that aged gins are great for replacing whiskey in classic cocktails such as a mint juleps, Sazeracs, old fashioneds, and Manhattans, and these are best enjoyed without too many modifiers or juices.
“Just enough to balance it,” he says.