Stouts aged in whiskey barrels first appeared more than 25 years ago, with the introduction of Goose Island’s now-iconic Bourbon County Stout. The concept quickly gained fans and momentum. For more than a generation, these limited-edition, barrel-aged imperial stouts have become cult favorites, with Goose Island moving to a lottery system for its nationwide release on Black Friday in 2020, and Toppling Goliath also using a lottery to release its Kentucky Brunch Brand Stout on Dec. 5.
Now, distilleries are playing a similar game by effectively reversing the process, creating special, often highly limited beer-barrel and ale-cask finishes for their own spirits.
While it might sound like a marketing gimmick, distillers say the process truly adds something. At Teeling Whiskey in Ireland, Alex Chasko, the master distiller, believes that beer-barrel finishes can bring new flavors to a classic dram, like his Teeling Stout Cask.
“I think the main thing that the stout cask particularly brings is that roasted-barley bitterness to it, and that plays well against the sweetness,” he says. “At least in our whiskey, we have an underlying sort of honey, vanilla sweetness. And so, you get that juxtaposition there, the bitter and the sweet against each other, which works nicely.”
In addition to new flavors, distillers say that beer-barrel finishes can also elevate notes already present, even if the effect is just slight.
Chris Fletcher, Jack Daniel’s master distiller, created a stout-cask release for his Tennessee Tasters’ Selection series, limited to the brand’s home state. Called Barrel Reunion #2, it was aged in barrels that previously held an oatmeal stout. It amplified an aspect of the whiskey’s traditional flavor profile, which surprised Fletcher.
“I would say it added a really nice kind of cooked-fruit note,” says Fletcher. “Jack Daniel’s has a bit of a fruity, ester-y aroma at heart, as part of how our yeast and fermentation expresses itself. I was not involved with the beer-brewing process, but there was something around that particular oatmeal stout that really accentuated that. It really made it more of a cooked fruit, more like a cherry pie.”
The beer barrels can also add subtler, stylistic changes. Many ale-cask whiskeys end up at least a shade darker after they’re aged in a barrel that once held a dark beer, like a stout or porter.
The process can even alter the mouthfeel of the whiskey.
Perhaps the most famous beer-barrel finishes come from Jameson. Its Caskmates series launched in 2015 with vessels that had held stout from a small brewery near its home in Cork, Ireland, before moving on to an IPA edition and other versions seasoned in former beer barrels from craft breweries around the globe.
Dave Quinn, Jameson’s “master of whiskey science,” says that the first release showed how that the process could affect the spirit’s mouthfeel, while it also added flavors like cocoa, butterscotch and coffee.
“We were finding that the texture of the whiskey had changed,” says Quinn. “It had softened a bit more. Normally, Jameson, coming from a whiskey that’s primarily distilled in pot stills from barley and malted barley, has a sort of creamy feel or texture to it. And this was adding a degree of softness to the taste. That’s what really, in our view, sets it apart from the regular Jameson whiskey.”
While the process might seem straightforward, there can be hurdles. Most breweries had been aging beers in stainless steel vats, not wooden barrels, for close to a century now. And so, if beer-seasoned barrels are needed, distillers generally have to visit a brewery first.
That gave rise to the “Barrel Reunion” line at Jack Daniel’s, Fletcher says.
While it might sound like a marketing gimmick, distillers say the process truly adds something.
“All of those barrels that we’ve done so far on the Reunion line are our barrels,” says Fletcher. “They were made by our coopers. Those staves were cut by our people that are working in our stave mills. They were toasted, charred, filled with our Jack Daniels whiskey, first as a brand-new, charred-oak barrel. [The barrels] fully aged Jack Daniels. Once that whiskey was dumped, then we sent the barrels to the brewery.”
Considering the long-running interest in barrel-aged beers, it’s not hard to find breweries that are interested in acquiring used whiskey barrels. In San Francisco, Old Potrero gave some to its old partner Anchor Brewing, conveniently housed in the same building, before the distiller used those barrels again to finish its whiskey.
But if the brewery and the distillery aren’t so close in proximity, there can be spoilage problems. To ensure its Caskmates barrels don’t grow mold or otherwise go bad, Jameson ships them back from partner breweries in refrigerated containers “as quickly as possible,” says Quinn.
An additional challenge is yeast left in the barrel by the beer, which often requires filtration for the whiskey.
“Some beer drinkers don’t have any issues with cloudy beer,” says Quinn. “Whiskey drinkers don’t tend to appreciate cloudy whiskey.”
While beer-barrel whiskey might sound like a marketing ploy, according to distillers like Fletcher, it’s more of an homage. The old world of whiskey, he says, has simply found inspiration in modern craft beer.
“When we view the current state of American whiskey production and this innovation focus, we see a lot of whiskey consumers now in the U.S. that are interested in trying new flavors and new things,” he says. “I mean, there’s a lot of great brewers out there. And honestly, breweries have been innovating and pushing the envelope on flavors, especially here in the U.S., for far longer.”