In search of the perfect finish

Do beer-finished whiskies really add anything?


Since William Grant & Sons’ Master Blender David Stewart began experimenting with ex-Sherry barrels in the 1980s, a diverse range of casks – from fortified to sweet wine and from rum to Cognac – have been used to “finish” whisky. 

Whisky finishing has a similar purpose to dry hopping in beer: it’s a “secondary maturation” aimed at boosting the liquid’s complexity that consists in transferring the whisky from one type of cask into another and letting it suck on its flavours for a short time before bottling.

Beer casks are unusual candidates for the finishing process; unlike wine – and most spirits – beer spoils easily in wooden casks and tends to release little flavour onto the barrel. Despite this, Stewart’s inquisitive nature led him to begin investigating beer’s potential as a cask seasoning agent in the 1990s, at a time when the global craft beer revolution was still in its infancy. The result of his pioneering work, Grant Ale Cask, was released in 1998. “David Stuart was a bit of what you call a Willy Wonka,” says Grant’s Danny Dyer. To source the beer needed for cask seasoning, Grant tapped Edinburgh’s Caledonian brewery. “I believe the beers were a light, a heavy, an export, and a strong Scotch ale,” Dyer recalls. “They put them into first-fill bourbon barrels and it turned out that the best result came by using the beer with the highest abv. I think it was about 8%-ish.”

The lower abv beers’ flavours seem not to be capable of holding onto the wood. “The wood was too overpowering. That higher abv was what gave us that toffee, caramel, almost gooseberry aromas.”

Glenfiddich found in a higher-alcohol beer a winning card too when, almost two decades later, they launched IPA Experiment. “Most beers struggle to push flavour against whisky,” says brand ambassador Mark Thomson. “The beer that we put into the cask was about 7% abv, to combat the alcohol in the whisky and when it came out the beer’s abv had lifted to above 9% because it sucked some of the alcohol that was inside the cask.” 

Thomson points out that the expression was designed to “appeal to those who were coming into whisky for the first time or reluctant to start their whisky journey. You could go into a pub and there’s a selection of whisky with so much to choose from and ‘IPA cask finish’ is something easy to understand”. Britain’s ever-rising craft beer drinking population was a clear target: “We launched the IPA Experiment at a London craft beer festival. It was quite interesting to see how people interacted with it because they were not used to seeing a whisky at a beer festival. We had quite a few people coming by, by their own admission not whisky drinkers. They would say: ‘it doesn’t smell how I expected it to be’.”

Since its launch, Glenfiddich IPA Experiment opened the distillery’s doors to a younger crowd who would have never approached whisky, and Scotch in particular, otherwise.

With their Caskmates Series – which consists of the year-round Stout and IPA Editions as well as a number of limited, regional releases – Ireland’s Jameson walked a similar path.

“It definitely opened Jameson’s market up to a new audience,” confirms Shane Long, the distillery’s original partner brewer. “The Caskmates Series’ audience would incorporate the traditional whiskey drinker, but the bulk would be much younger.”

Targeting a younger crowd however, wasn’t Jameson’s initial plan. Long points out that the Caskmate Series happened by accident, after he had approached the distiller to source some casks to employ for a personal barrel-aged beer project. “At the time I had a very small brewery in Cork and was looking at ways of expanding my business, how to achieve a better margin and a better price point. We were in demand in the US and one distributor recommended getting into barrel ageing so I approached Irish Distillers [which owns Jameson] to see if they would give me some casks.”

They accepted to give him some barrels with the stipulation that he couldn’t put the distillery’s name on the beer and that they had to test its quality before its release, “because they didn’t want their name associated with anything that they viewed as an inferior product”.

The beer was eventually a success and, after a bit of reluctancy, they took the casks back. They filled them up again with whiskey and forgot about them until six months later, when they realised the liquid had “immediately picked up the malt’s notes. They put them through the bottling line and it went from zero to 300,000 cases in just a couple of years”.

Long, who partnered with Jameson until 2019, says he experimented with different temperature controls to speed up the time the beer needs to spend in the cask. He claims the process is unique to him, somehow inspired by the Caribbean climate, where rum matures faster than it would do in Ireland. Having trialled different beer styles, Long says that some “impart flavours to the whisky that just do not work”, while Stout and IPA were clear winners.

Having trialled different beer styles, Long says that Stout and IPA were clear winners

Tapping on Ireland’s chauvinistic devotion to the style, Stout cask finishes have experienced a certain popularity among Irish distilleries. Dublin Liberties Distillery’s Master Distiller, Darryl McNally created a Beer Cask Series whose first iterations were finished in Rascals Brewing Coffee Stout and in O’Hara’s Irish Stout, while West Cork Distillery released a blended whiskey finished in Blacks of Kinsale’s brewery Stout. “The beer is taken from the brewery and intensified by removing water by means of filtration,” says West Cork R&D Manager, Jan Hodel. “This is done to concentrate the flavour of the beer. Afterwards, the concentrate is casked in… second-fill ex-Bourbon barrels [for] at least a year.” He believes that the Stout’s aromas of “vanilla, cappuccino, orange liqueur and angelica root” are ideal candidates to complement a whiskey, but highlights that the IPA is a pretty good contender too. For Hodel, the IPA cask introduces freshness, aromas of “apples, wine gums, lime, tequila and peppery notes”. He points out that hop aromas are capable of lending the whiskey a very distinctive character with no risk of aromatic decline. “Unstable terpenes from hops would have [already] undergone reactions during the resting period [and] high volatile compounds would have evaporated during this time. The flavour compounds which end up in the whiskey would be mostly stable and from what we discovered so far they stay mostly the same.”

Glenfiddich’s Thomson also sees in the IPA the ideal cask seasoning beer style, optimal to lend the whisky an individual, novel character. Glenfiddich’s IPA was created in partnership with Seb Jones of Speyside Brewery, using lots of Challenger hops both in the boil and at the dry hopping stage “to push it right up with its orangey notes”. The beer was designed with the sole purpose of seasoning the cask and not for commercial purposes, so “it’s undrinkably bitter. Honestly, I don’t know what happens to the beer once it’s out of the cask. We went for Challenger for its muted orange character as it complements the whisky’s aromas. Glenfiddich new-make has a very grassy, herbaceous note to it but then takes on a orangey note after it’s been matured in cask.”

The popularity of IPA-cask finished whiskies expanded well beyond Scotland to land on Japanese shores. Nagano Prefecture-based Shinshu Mars distillery boasts a limited-release beer cask finish made using an IPA from nearby Minamishinshu brewery and even world-renowned Chichibu launched its own IPA-themed version. Hiroshima-based Sakurao Brewery & Distillery pushed the potential of beer-cask finishing further: their Togouchi blended whisky is finished for four-to-eight months in 10yo rhum agricole barrels from Martinique that have been seasoned with “IPA beer in France” for 14 months.

Thomson believes the IPA style is such a great match for whisky that he advises drinkers to consume one alongside Glenfiddich’s IPA Experiment. “In Scotland there is a very traditional way of drinking whisky,” he says, “it’s called Half and Half. A bit like an American Boilermaker, but unlike the Boilermaker (where you shoot the bourbon), you alternate between a smaller serve of beer and a dram of whisky.” He took the idea to the next level when he teamed up with Glasgow’s West Brewery and nine whisky bars across Scotland. The team spent two days at the brewery designing a beer to match Glenfiddich IPA Experiment. “The result is a limited edition sessionable IPA that was supposed to be in the conditioning tank for five weeks, but eventually because of Covid it sat in there for nine months. The head brewer told me it turned out to be one of his favourites ever.”

Dyer says that the Half and Half was in fact crucial to the birth of Grant’s Ale Cask, too. “Stewart was at the pub with the chief chemist,” he says, speaking of the whisky’s origin. “They ordered a Scotch and a beer ‘chaser’. They looked at each other and said ‘you’re thinking what I’m thinking?’, and they both nodded.” Beer-cask finished whiskies aren’t simply a ploy to attract a younger, whisky shy crowd. They represent the latest iteration of a beer-whisky love affair deeply rooted in historical whisky and beer drinking cultures. One that, for daring distillers, still veils an immense potential to untap.

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