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More on Whisky-making: What happens during the barrel-aging process? Can the aging process be accelerated?


What you should know

  • One essential feature of whiskies is that they are aged/matured in a cask for at least 3 years. This is intended to smoothen the spirit and create more complexity.
  • However, a group of new whisky and rum makers believe science can help them bypass the barrel-ageing process
  • California-based Lost Spirits Distillery claims to have developed a process that can put spirits through decades’ worth of ageing in just a few days using heat and light
  • We examine whether this is legit by doing a deep dive into the traditional maturation process, and Lost Spirits’ aging process.
  • Our quick take:
    • We should be open-minded to recognising “instantly-aged whisky” as whisky, so long as the quality of the spirit is not inferior to traditionally-made whiskies.
    • Lost Spirits appears to be able to create a spirit with a similar chemical footprint as 15-year barrel-aged whisky. We, and established reviewers, have found that they taste respectable.
    • Traditional whisky makers cannot be fully replaced by 6-day rapidly-aged “reactor” whiskies.


Our earlier post entitled “What is whisky?” defines whisky as an alcoholic drink that is made by fermenting barley, corn or rye into a beer, distilling the beer into a spirit, and finally aging it in a barrel for years.

In recent years, we are seeing more and more players in the industry coming up to challenge this definition. For instance, we have observed the new Kikori Distillery which uses rice (instead of barley, corn or rye) to create “whiskey”, leading to controversy about possible deceptive advertising and heated philosophical discussions on whether you can label rice-distilled spirits as whisky

Let’s consider another essential feature of whisky- the years that go into aging the spirit. Regulations in Scotland, England, Ireland and Japan specifically provide that the spirit cannot be labelled as whisky unless it has been aged for a couple of years (usually at least 3 years) in wooden casks before it may be labelled as whisky.

What if I tell you that the aging process can be accelerated by technology? What if there is a special vessel in which time passes 10 times faster than in our world, so that you could put your whisky through decades worth of aging within the span of a week? Would the by-product be considered whisky?

To answer these questions, today we shall look into: (1) what happens during the barrel-aging process and (2) the taste and quality of “Abominations” created by an “instant-aging” process.

But first, some context on the “instant-aging” hype and controversy.


“Instant-aging” technology


Bryan Davis of Lost Spirits Distillery, with his “instant-aging” reactors (Image Source: Peter Yang, Whisky Advocate)


The California-based Lost Spirits Distillery has an outlandish claim that you can do precisely that: age a spirit 30 years within the span of several weeks with the use of a patented reactor, heat, UV light, ultrasound, high pressure and tiny fragments of wood. Lost Spirits is but the highest profile of many other new whisky and rum makers who believe science can be used to “hack” the spirit-ageing process. Bryan Davis, the co-founder of Lost Spirits confidently quipped:

It’s very likely that this will end up being the way everybody makes [aged spirits] 100 years from now”.


The whisky industry is unamused

The mainstream whisky industry (that invests substantially in the traditional ageing process) is neither enthusiastic nor amused by the claims of newcomers like Davis.

The Scotch Whisky Association label these products as essentially counterfeit, reminding the public that many countries have legal definitions of whisky that require a specified period of barrel-ageing. Alan Park, a spokesperson says:

For me, accelerated ageing is a contradiction in terms. Maturation in a cask is a complex reaction. You simply don’t get the same spirit by using artificial processes. We should just put them back in their box and say, ‘Do what you want, just don’t call it whisky.’

Diageo, the world’s largest whisky distiller, also rejects the idea of “instantly-aged” whisky. 

Should we be surprised considering their vested interest though?


A deep-dive into the complex barrel-aging process

So, what exactly is the magic of the barrel-aging process? What happens during the aging process? Is it impossible to induce these changes within a shorter span of time?

Maturation smoothens out the harsher notes in the spirit and creates more complexity in the flavour of the spirit. It is a complex process involving an interaction between the alcohol, aromatic substances in the spirit, the barrel wood, and remnants of the liquid that the barrel used to store (e.g. bourbon, sherry or other wines).

Three main types of reaction occur – (1) additive, (2) subtractive and (3) interactive.

Additive. The spirit takes up flavours of the cask. Compounds from the oak (wood lignins, tannins and cellulose) impart flavours to the spirit lending notes of vanilla, caramel, toffee and even coconut. The bourbon or sherry residue in the wood also imparts flavours into the spirit, from the bright crème brulee sweetness of bourbon (due to high corn content), to the dark fruits, nuttiness and dryness of sherry. 

Subtractive. New make spirit are harsher tasting and sometimes contains a tangy, metallic taste. The oak absorbs undesirable elements of the spirit including the pungent sulfur compounds, such as dimethyl sulfide. This removes the more aggressive new-spirit character and makes the spirit smoother.

Interactive. The compounds also interact with each other. And as oxygen diffuses into the porous barrels, reactions take place between the molecules in the spirit, and between the spirit and the wood. Alcohols and aldehydes are oxidised, and acids react with ethanol to form esters – which are some of the most aromatic of whisky flavour compounds responsible for fruity aromas. The lignin from the wood undergoes “ethanolysis”, where ethanol breaks down lignin into other flavour compounds including aromatic aldehydes. The by-products of earlier reactions also feed off other reactions down the line.


Casks upon casks of whisky at Bunnahabhain Distillery during a chilly January


To add to this complex equation, terroir certainly also affects the flavour of whisky. Apart from the source of the barley, the air and weather conditions in the area where the casks are stored have an impact too. During warm summer months, the barrels warm up and expand, while in the cold winter months the barrels contract, thereby "breathing" the surrounding air through the pores of the oak wood. Two things happen:

  • The air outside the cask is absorbed by the wood and oxidises the liquid, stimulating the creation of aromatic esters.
  • The environment and quality of the air also has an effect. For instance, on Islay with a coastal environment, the salty sea air is absorbed into the casks. This is why many seaside-distilleries (think Talisker) have a hint of maritime profile.

It is clear from the above that the barrel-aging process is extremely complex. Distillers have been trying to speed up the process for more than a century, says the whisky writer Ian Buxton. Few have succeeded. 

But why should we be sure that no one would ever succeed?


Introducing the Lost Spirits Distillery

The idea of rapid maturation inflames strong passions amongst traditionalists of the whisky world. It is possible to imagine this as a generational critique by traditionalist boomers on millennials who no longer value time, tradition, patience and craftsmanship.

Yet, what appears to really annoy some traditionalists of the whisky world how Lost Spirits received its fame. Lost Spirits was a relatively obscure distillery until it was catapulted to mainstream discussions in 2017 when the distillery received one of the highest accolades from industry veterans for its “instantly-aged” spirits. Lost Spirits entered its two peated malt “whiskies” tempered with its “instant-aging” technology for judging under Jim Murray’s 2018 Whisky Bible competition. Both bottles were awarded impressively high scores – 94 and 93 respectively with one receiving the coveted Liquid Gold designation by veteran critics. Not surprisingly, there are many skeptics. However, other reviewers who have tasted the bottles have generally found that they taste respectable and comparable in flavour to traditionally aged whisky. 

Lost Spirits continues to produce the same two bottles of Abomination (that’s the name of their “whisky” range)- “The Sayers of the Law” expression and the “Crying of the Puma” expression. Both are heavily peated.


(Image Source: Drinkhacker.com)


Making the “instantly-aged” Abominations

Both Abominations begin their life much like a traditional single malt: both are made from heavily peated malted barley and distilled in an Islay distillery just like a traditional single malt, and aged (in the conventional way) for 12 - 18 months. They are then transferred to the Californian Lost Spirits’ laboratory, poured into a steel reactor and tempered for a grand total of 6 days while interacting with Riesling-seasoned charred American oak. 

After 6 days in the reactor, the spirit would have undergone the same reactions seen through years of traditional maturation,and emerge with a similar chemical fingerprint as a 15-year-old whisky

How does this seemingly-miraculous process work? In summary, the technology tries to create as much esters and other flavour compounds as possible in a very short amount of time. The Bryan Davis of Lost Spirits explained:

“The technology works by exposing oak to high intensity light and heat while suspended in a glass tube filled with unaged or young distilled spirit. The combination of specific wavelengths of light and heat has been proven to trigger the same chemical reactions that happen in casks aged for many years.”


Davis’ patented reactor (Source: https://patents.google.com/patent/US9637713B2/en)


Davis’ process of developing the “instant-aging” technique was heavily guided by detailed scientific analysis. To understand the traditional maturation process, he created a chromatogram library of traditionally-aged whiskies. Subjecting a wide range of traditional whiskies to mass spectroscopy, he could reveal the constituents of those whiskies, such as certain sugars and/or chemicals are contained in the most desirable classic whiskies. 

After a series of experiments, Davis developed and configured his reactors to support his “instant-aging” technique. A series of reactors are used. 

One reactor is known as the “esterification reactor” which take all the raw acids from the spirits and forces them to bind to the ethanol, creating long-chained esters with a range of floral, honey, fruity, earthy, nutty and medicinal aromas. 

Another reactor is known as the “extraction reactor” which is extract all the necessary aldehydes, phenols, acids, lignins, tannins and cellulose from the wood, and impart their flavours to the spirit (sound familiar?). Usually, many years are required to chemically breakdown the wood to release these compounds. However, Davis developed a method of firing high-speed particles at the wood, creating a light three times the intensity of the Sun at noontime on the equinox. When the radiation shatters the wood structure, the wood in Davis’ words, “gives you everything in two days that it would have given you during twenty years in the barrel”.


An “instant-aging” reactor which processes spirit and wood with intense light at Lost Spirits (Image Source: Bryan Davis)


Our take on “instantly-aged” whisky



We were extremely curious about Lost Spirits’ antics and have taken the trouble of procuring a bottle for our tasting. And we think that it is a delightful Islay-style expression.

My position is that we should be open minded to recognising “instantly-aged whisky” as whisky, so long as the quality of the spirit is not inferior to traditionally-made whiskies.


The laboratory at Lost Spirits (Image Source: @pricef from Instagram)


A large reason for scorn against “instant-aging” is the assumption that such “whisky” makers are run by flannel-shirt wearing hipsters in California who are trying to cut corners and make a quick buck with the hype. But considering the amount of thought and analysis put into this by Davis and Lost Spirits Distillery, I disagree with the criticism.

The traditional process of aging spirits is a complex process of interaction between the alcohol, aromatic substances and wood to create the desired aldehydes, esters and flavour compounds. But do traditional whisky makers, using the same processes as their ancestors 300 years ago, know exactly what reactions are going during the aging process? Probably not.

Upcoming whisky makers such as Lost Spirits know exactly what they are doing. It’s absolutely possible for them to develop methods to extract flavour compounds from the oak in two days that would otherwise have taken 20 years to extract by natural wood decomposition. There’s also nothing to stop these folks from using mass spectrometry to study the chemical composition and profile essential molecules that make whisky taste good, and then use processes to create these molecules. All it takes is some research and scientific finesse.

But of course, I wouldn’t agree that a whisky processed for a mere 6-days in a patented reactor can be labelled as a 30-year old whisky (or priced the same)!


What would happen to tradition?


(Image Source: Visit Scotland)


That said, the unease of everyone in the whisky world is completely understandable. 

Orthodox whisky drinkers demand a certain integrity to craftsmanship in the 300-year-old art and culture of whisky appreciation. Tradition and time instils a sacred purity to this process and elevates the mechanical process of making whisky into a sort of religion. Incremental innovation whilst preserving tradition is welcome, but transformative and disruptive innovation would be considered blasphemy. 

At the end of the day, it’s already 2021 and the progress of scientific advancement is inexorable. Traditional whisky makers should rest easy that they cannot be fully replaced by 6-day finished Californian “reactor” whiskies. There would always be a town big enough for both the traditionalists and the avant garde, at least for our generation.