Where would whisky be without the humble wooden cask? Probably stuck in the dark ages of clandestine moonshine and mountain dew rather than the amber-dappled drams of modernity.
The cask is undoubtedly one of the most important contributors of character to a whisky, with some folks even arguing the wood accounts for up to 70 per cent of a whisky’s final flavour. It doesn’t matter if it’s bourbon, single malt, or rye – the cask is king. And a distillery’s wood policy can make or break the spirit it produces.
Coming off the still at somewhere between 60–90% ABV, new-make whisky, no matter the style, is often powerful stuff. Put the liquid inside an oak cask and after a few months the hard edges have softened, and the fiery new-make heat is slightly quenched. Come back a few years later and the whisky has taken on a lovely golden to reddish hue. Well-matured whisky springs forth from its wooden chrysalis polished and primed for sipping.
Of course, this all takes time. Lots and lots of time – years, usually. Sometimes a whisky won’t truly hit its peak until well into its second decade. And sometimes it takes even longer than that. But, like in any other industry, time is money and all that waiting on mother nature isn’t cheap.
To circumvent the inconvenience of time, some producers have taken to the laboratory in efforts to hack the arcane maturation code so long obscured by nature. However, what were once considered fringe practices by a few whisky-loving kooks have increasingly become accepted by more serious consumers looking for innovation in their drams.
In general, there are four major classes of reactions happening inside the cask. Additive reactions are the direct extractions of wood components into the spirit. These components include things such as wood sugars, colour compounds, lactones, wood acids, and tannins.
Subtractive reactions are where the wood actively removes substances from the spirit. The most cited example of this is the removal of various sulfides in whisky by the activated carbon in the oak char layer. These sulfides, which include dimethyl sulfide and dimethyl trisulfide, can contribute aromas of cooked corn and vegetables if left unchecked, so the cask is doing a serious service for the whisky here.
Productive reactions are where compounds are chemically formed or otherwise created in the cask. This includes the ethanolysis of lignin, an important structural compound in woody plants. The ethanol from the spirit (in addition to the heat treatment used in the production of the cask) will slowly break down lignin into a variety of important aroma compounds, such as vanillin. Also included in this group is the formation of esters which are an incredibly important piece to the maturation puzzle.
Finally, there are the reductive reactions where compounds are chemically reduced in amount. One of the most important of these is the reduction of a compound called acrolein. Acrolein is found in most new-make spirits to some degree, as it is formed inside the still through the heated transformation of glycerol. Acrolein has a sort of horseradish-style heat to it and is one of the reasons new-make spirits often taste hot, fiery, and pungent. However, through gentle oxygen ingress into the cask wood, over time acrolein is reduced to the non-taste threatening acrylic acid.
Clearly, there’s a lot going on inside the cask and the above examples hardly scratch the surface. This is perhaps why the world of rapidly matured spirits has had so many difficulties finding its footing over the years. The technologies and techniques being used often address only one or two of the major reaction categories and the subsequent spirit is usually unbalanced at best.
Gary Spedding is a well-known researcher in the realm of spirits and beers, and he has written extensively on the problems facing rapid-maturation technologies. When asked why so many of these technologies have traditionally stumbled on the road to producing something remotely drinkable, he said: “…reactions proceed to a certain end point. Some to completion and some to equilibrium. And there are hundreds of these reactions taking place.
“You need to know details of these hundreds of reactions before mucking about and adding or subtracting things to try to drive desired reactions one way or the other.”
It’s an important point, but that has not hindered the efforts of several producers working in this unique space. Instead, mysteries such as this have only emboldened a few distillers to further research and suss out what’s happening inside the cask.
Tom Lix is the founder of Cleveland Whiskey, a distillery located in Cleveland, Ohio. After years of experimentation and tinkering, he has arrived at a process and technology uniquely suited to his fascination with wood flavour. He matures his bourbon for a period of roughly six months before placing it inside specially designed steel tanks along with the wood of his choosing. The tanks allow him to control temperature, oxygen, pressure, and liquid movement. Over a period of days or weeks, the nascent whiskey takes on more mature characteristics, as well as notes from the additional wood dosage.
Lix says that he’s had to deal with his fair share of sceptics. He even admits that his earliest whiskeys were not his proudest moments. However, he knew he was on to something. He just had to tinker and tweak. Using his technology allows him to add unique woods that few distillers have been willing to try on a cask-sized scale. Some of the woods he has successfully used include apple wood, black cherry, and honey locust. These days he’s selling whiskey about as fast as he can make it and taking home numerous prestigious awards while he’s at it.
Newer to the scene are the gentlemen from Bespoken Spirits in California. Started by two friends, Martin Janousek and Stu Aaron, both from the tech industry in Silicon Valley, Bespoken has also developed its own proprietary technology for putting the effects of nature into overdrive. They produce a number of their own bottlings but also work under contract as a producer for other customers. They say some people want to produce and move their own brands to market, while others want to use their technology to simply spec and see the results of twisting the knobs on various parameters in their own production facilities. The technology that Bespoken has built allows it to gather immense amounts of data and dial in recipes with laser precision.
On top of all that, the team’s method is one of the more eco-friendly tracks taken in the industry. They claim that they are using only about three per cent of the wood and one per cent of the energy in their processes compared to standard whiskey production. The results speak for themselves. Bespoken is also raking in awards and accolades from the whiskey industry’s biggest press and competitions.
When asked about whether or not they felt they had cracked the code to mother nature’s liquor cabinet, Martin was quietly humble but confident. “It’s not about taking a spirit from A to B on a timeline… For us, it’s really about the customisation part; to really customise the flavours… So yes, hopefully, we’ve cracked the code. But we want to go much further.”
No investigation into these techniques and technologies is complete without handing the mic over to Bryan Davis of Lost Spirits. Beginning in Northern California wine country around 2009, Bryan and his partner Joanne have been experimenting with rapid-maturation methods in whiskey from the earliest years of Lost Spirits. The goal, however, was not to speed things along but rather to find a process that would give some kind of indication of how the various barrels they were using from Napa Valley would behave with their whiskeys.
Bryan says, “I started running some experiments, playing around with chopping up the different barrels I was sourcing and then heating them with the booze to see what would happen. And I just sort of by happenstance stumbled my way onto the fact that if you heated it up to just the right temperature you could trigger the esterification seemingly on demand.”
What Bryan stumbled onto was a solution to a problem that has long vexed many spirits producers. These esterification reactions, which provide a wide array of complex and fruity aged aromas in spirits, were some of the reactions that took the longest. These reactions also contribute a lot to the overall ‘mature’ character of a spirit.
Bryan followed through on the results, eventually designing his THEA One reactor for building and tweaking spirit character, with often fantastic results.
If there is a common thread that has woven itself through all these producers’ philosophies, it’s that the means are more important than the end. Lix, Davis, and Janousek have all spoken about how the goal is less about getting a mature-tasting spirit faster and more about being able to tweak and tinker with spirit character in an accelerated time frame. It’s about joyous experimentation and the resultant data points, which can help producers better understand the maturation process as a whole.
Importantly, it’s not yet an exact science. As Bryan Davis says, “I always end up going from one failure to the next while still being fairly entertained.” Now, that’s the spirit.
The cask is undoubtedly one of the most important contributors of character to a whisky, with some folks even arguing the wood accounts for up to 70 per cent of a whisky’s final flavour. It doesn’t matter if it’s bourbon, single malt, or rye – the cask is king. And a distillery’s wood policy can make or break the spirit it produces.
Coming off the still at somewhere between 60–90% ABV, new-make whisky, no matter the style, is often powerful stuff. Put the liquid inside an oak cask and after a few months the hard edges have softened, and the fiery new-make heat is slightly quenched. Come back a few years later and the whisky has taken on a lovely golden to reddish hue. Well-matured whisky springs forth from its wooden chrysalis polished and primed for sipping.
Of course, this all takes time. Lots and lots of time – years, usually. Sometimes a whisky won’t truly hit its peak until well into its second decade. And sometimes it takes even longer than that. But, like in any other industry, time is money and all that waiting on mother nature isn’t cheap.
To circumvent the inconvenience of time, some producers have taken to the laboratory in efforts to hack the arcane maturation code so long obscured by nature. However, what were once considered fringe practices by a few whisky-loving kooks have increasingly become accepted by more serious consumers looking for innovation in their drams.
In general, there are four major classes of reactions happening inside the cask. Additive reactions are the direct extractions of wood components into the spirit. These components include things such as wood sugars, colour compounds, lactones, wood acids, and tannins.
Subtractive reactions are where the wood actively removes substances from the spirit. The most cited example of this is the removal of various sulfides in whisky by the activated carbon in the oak char layer. These sulfides, which include dimethyl sulfide and dimethyl trisulfide, can contribute aromas of cooked corn and vegetables if left unchecked, so the cask is doing a serious service for the whisky here.
Productive reactions are where compounds are chemically formed or otherwise created in the cask. This includes the ethanolysis of lignin, an important structural compound in woody plants. The ethanol from the spirit (in addition to the heat treatment used in the production of the cask) will slowly break down lignin into a variety of important aroma compounds, such as vanillin. Also included in this group is the formation of esters which are an incredibly important piece to the maturation puzzle.
Finally, there are the reductive reactions where compounds are chemically reduced in amount. One of the most important of these is the reduction of a compound called acrolein. Acrolein is found in most new-make spirits to some degree, as it is formed inside the still through the heated transformation of glycerol. Acrolein has a sort of horseradish-style heat to it and is one of the reasons new-make spirits often taste hot, fiery, and pungent. However, through gentle oxygen ingress into the cask wood, over time acrolein is reduced to the non-taste threatening acrylic acid.
Clearly, there’s a lot going on inside the cask and the above examples hardly scratch the surface. This is perhaps why the world of rapidly matured spirits has had so many difficulties finding its footing over the years. The technologies and techniques being used often address only one or two of the major reaction categories and the subsequent spirit is usually unbalanced at best.
Gary Spedding is a well-known researcher in the realm of spirits and beers, and he has written extensively on the problems facing rapid-maturation technologies. When asked why so many of these technologies have traditionally stumbled on the road to producing something remotely drinkable, he said: “…reactions proceed to a certain end point. Some to completion and some to equilibrium. And there are hundreds of these reactions taking place.
“You need to know details of these hundreds of reactions before mucking about and adding or subtracting things to try to drive desired reactions one way or the other.”
It’s an important point, but that has not hindered the efforts of several producers working in this unique space. Instead, mysteries such as this have only emboldened a few distillers to further research and suss out what’s happening inside the cask.
Tom Lix is the founder of Cleveland Whiskey, a distillery located in Cleveland, Ohio. After years of experimentation and tinkering, he has arrived at a process and technology uniquely suited to his fascination with wood flavour. He matures his bourbon for a period of roughly six months before placing it inside specially designed steel tanks along with the wood of his choosing. The tanks allow him to control temperature, oxygen, pressure, and liquid movement. Over a period of days or weeks, the nascent whiskey takes on more mature characteristics, as well as notes from the additional wood dosage.
Lix says that he’s had to deal with his fair share of sceptics. He even admits that his earliest whiskeys were not his proudest moments. However, he knew he was on to something. He just had to tinker and tweak. Using his technology allows him to add unique woods that few distillers have been willing to try on a cask-sized scale. Some of the woods he has successfully used include apple wood, black cherry, and honey locust. These days he’s selling whiskey about as fast as he can make it and taking home numerous prestigious awards while he’s at it.
Newer to the scene are the gentlemen from Bespoken Spirits in California. Started by two friends, Martin Janousek and Stu Aaron, both from the tech industry in Silicon Valley, Bespoken has also developed its own proprietary technology for putting the effects of nature into overdrive. They produce a number of their own bottlings but also work under contract as a producer for other customers. They say some people want to produce and move their own brands to market, while others want to use their technology to simply spec and see the results of twisting the knobs on various parameters in their own production facilities. The technology that Bespoken has built allows it to gather immense amounts of data and dial in recipes with laser precision.
On top of all that, the team’s method is one of the more eco-friendly tracks taken in the industry. They claim that they are using only about three per cent of the wood and one per cent of the energy in their processes compared to standard whiskey production. The results speak for themselves. Bespoken is also raking in awards and accolades from the whiskey industry’s biggest press and competitions.
When asked about whether or not they felt they had cracked the code to mother nature’s liquor cabinet, Martin was quietly humble but confident. “It’s not about taking a spirit from A to B on a timeline… For us, it’s really about the customisation part; to really customise the flavours… So yes, hopefully, we’ve cracked the code. But we want to go much further.”
No investigation into these techniques and technologies is complete without handing the mic over to Bryan Davis of Lost Spirits. Beginning in Northern California wine country around 2009, Bryan and his partner Joanne have been experimenting with rapid-maturation methods in whiskey from the earliest years of Lost Spirits. The goal, however, was not to speed things along but rather to find a process that would give some kind of indication of how the various barrels they were using from Napa Valley would behave with their whiskeys.
Bryan Davis
Bryan says, “I started running some experiments, playing around with chopping up the different barrels I was sourcing and then heating them with the booze to see what would happen. And I just sort of by happenstance stumbled my way onto the fact that if you heated it up to just the right temperature you could trigger the esterification seemingly on demand.”
What Bryan stumbled onto was a solution to a problem that has long vexed many spirits producers. These esterification reactions, which provide a wide array of complex and fruity aged aromas in spirits, were some of the reactions that took the longest. These reactions also contribute a lot to the overall ‘mature’ character of a spirit.
Bryan followed through on the results, eventually designing his THEA One reactor for building and tweaking spirit character, with often fantastic results.
If there is a common thread that has woven itself through all these producers’ philosophies, it’s that the means are more important than the end. Lix, Davis, and Janousek have all spoken about how the goal is less about getting a mature-tasting spirit faster and more about being able to tweak and tinker with spirit character in an accelerated time frame. It’s about joyous experimentation and the resultant data points, which can help producers better understand the maturation process as a whole.
Importantly, it’s not yet an exact science. As Bryan Davis says, “I always end up going from one failure to the next while still being fairly entertained.” Now, that’s the spirit.
