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How Many Times Has A Cask Been Used Until It Reaches The Scottish Whisky Industry?

Whisky casks

In 2019, The Scotch Whisky Association expanded the rules for ageing and finishing whiskies to include casks previously used to age spirits. Under the new guidelines, in addition to beer and wine, spirits like tequila, mezcal, calvados, and shochu, which are traditionally cask-aged, could be used to mature whiskies. However, gin and cider casks and spirits made with stone fruits and sweeteners are excluded from the list, as the spirits are not traditionally cask-aged.

Driven by the industry's rising need for oak casks, the guidelines provide whisky producers with much-needed assistance—just like rejuvenated wine barrels, STR, pioneered by the late Dr Jim Swan. The change has also expanded whisky's flavour profiles. However, all casks must still result in a spirit with the taste, aroma, and colour generally found in Scotch whisky.

The more relaxed rules have also introduced a conundrum that has yet to be widely discussed. When sourcing casks, for example, from tequila and rum producers, how many times have the casks already been used before reaching the Scotch whisky industry? And since barrels won't last indefinitely and wood does not impart a finite amount of flavour to whisky, how long can the Scotch whisky industry continue using them?

By tradition, the industry is familiar with refill casks, and virgin oak is rarely used because it is expensive. However, many other spirits also use previously used barrels from bourbon production because they are inexpensive compared to other options.

It all comes down to how well the history of a single cask is documented (or if it is) and what the whisky producer is looking to get from the cask. More often than not, barrels are broken down for shipping and reassembled by coopers at the destination, sometimes as bigger hogsheads, thus breaking down the character and possible tracking of a single barrel.

bourbon cask used in the Scotch whisky industry

Standard terms like first-fill, second-fill, and refill are used when ageing happens in traditional bourbon and sherry casks, and Scotch whisky is the second spirit to be matured. The bourbon industry only uses its casks once, as using virgin oak is regulated and set by the guidelines of the category. However, terms like 'rum-cask-finish' and 'aged in tequila casks' do not provide any information about the number of times the barrel has been used and if they are using them more than once. At the moment, companies are not required to give out the information. The lack of transparency provided to consumers raises the question of whether terms like 'first-fill rum cask' or 'second-fill tequila cask' should be used.

Whisky producers often use barrels that were previously used to age other spirits. It's generally recommended that whisky barrels are re-used at most four times in the trade, or two to three times (before they no longer impart flavour from the wine or spirit in the wood) for Scotch whisky, totalling around 50 years of usage. So, shouldn't we care about transparency regarding casks?

After all, each time a new spirit is put into a cask, it automatically becomes a first-fill barrel - in many ways erasing the understanding of the times the barrel has already been used.

Buffalo Trace bourbon cask

Image by Annandale distillery

If whisky is marketed as being matured in a specific type of cask shouldn't consumers deserve to know how many times the barrel has been used? With standard whisky casks, disclosing this information has become common practice. However, it's unclear whether consumers are getting whisky from a first-fill barrel or a refill barrel when it comes to many other types of casks new to the industry.

It's worth noting that most producers are honest and have years of experience in sourcing casks. They aim to produce the best whisky possible and are not trying to deceive consumers. However, they rarely disclose the full lifespan of the casks, leaving it to the imagination of consumers.

To shed some light on the matter, let's look at some of the cask types used to mature whiskies.

Please note, that all the barrel timelines for this article have been created by The Whisky Ardvark and should only be used as a reference depicting the possible lifespan of a barrel.


Sherry Casks

sherry casks

Image by Fundador

Spanish sherry casks have reportedly been used to age whisky since the early 1800s. At the time, sherry was incredibly popular in the UK, and whisky producers saw an opportunity to repurpose the barrels and reduce port clutter. This was before bourbon casks became widely available.

The flavours imparted by sherry casks became highly prized by producers. Traditionally, many sherries are aged in barrels for decades, allowing the spirit to penetrate deep into the wood. However, with the decline of sherry's popularity, many producers were left with unfulfilled needs. This led to the creation of Paxarette, or Pax for short.

WP Lawrie devised a solution to the shortage of ex-sherry casks by using an additive from the wine industry to rejuvenate tired sherry casks. Paxarette, made from fermented grape juice and concentrated Pedro Ximenez grape must, quickly gained popularity in the whisky industry, which desperately needed sherry casks. 

The additive was applied to the inside of the casks, much like paint, replicating the flavour and colour imparted by sherry casks. However, the Scottish Whisky Association banned its use in whisky production in 1990, making it illegal. Before the ban, Paxarette was widely used, so if you had a sherry cask whisky before 1990, chances are it was infused with Paxarette.

Today, some companies are addressing the shortage of sherry casks by using sherry-seasoned barrels. Often, the barrels have been previously used to age bourbon, after which sherry is added to the casks for two to five years. In addition, the sherry used to season the casks is often young and then used to make sherry vinegar or distilled to make brandy. Needless to say, sherry-seasoned casks do not provide as much flavour to the whisky as a barrel that has been used for decades to mature sherry.

sherry-seasoned cask used in the Scotch whisky industry

Due to the expensive nature of sherry casks, which can be five to ten times more costly than bourbon casks, many companies use them to finish whiskies - giving them a longer lifespan. This extra maturation does not have a minimum or maximum period but typically ranges from around three to 12 months.

Traditional sherry casks or butts were made of European oak, but increasingly, producers favour American oak casks from the bourbon industry. The sherry industry doesn't use virgin oak casks because of unfavourable tannins. Before sherry casks can mature sherries in the solera system, the barrels must have been used for ten years to rest wines.

traditional sherry cask used in the Scotch whisky industry

Unfortunately, it is impossible to say at what point in the barrel's lifespan in the sherry industry it was sold to the whisky producers. The producers keep some sherry casks for 100 to 200 years as prized casks, ultimately creating 'dead wood' where the barrel itself has lost its flavour-giving properties and serves as a mere container.


Rum Casks

rum casks

Image by Rum Auctioneer

As a relatively new addition to the whisky world, the first widely available rum cask-finished whisky, Balvenie 14-year-old Caribbean Cask, was launched in 2012.

According to regulations, rums do not require a minimum age, which is evidenced by the existence of unaged rums. While some rums are aged for one or two years, much older varieties are increasingly becoming available. Some countries only recognise rum as aged if it has been aged for at least 12 months.

Although some rums are aged in virgin oak or Cognac casks, most rum producers use American oak barrels, previously used to mature bourbon. Like in the whisky industry, these barrels can be used several times. But rum ages faster than whisky due to the warm climate and humidity in the Caribbeans.

rum cask used in the Scotch whisky industry

Determining the number of times a barrel has been used to age rum before being utilized in the whisky industry is challenging. While some producers disclose the precise rum that was previously aged in the barrel, additional information from the rum makers is required to enhance transparency in the industry.


Tequila Casks

tequila casks

Image by Beverage Dynamics

Tequila producers predominantly store and enrich their tequila in American oak casks from the bourbon industry. Unlike other spirits, these casks are used multiple times, up to five times, with each use having a gradual duration: one year the first, two years the second, and so on until reaching the fifth and last time. In optimal conditions, each tequila barrel can be used for a total of 15 years. 

Due to the humid and warm climate, the tequila barrels are watered on the outside with sprinkled water while they are full to prevent the spirit from evaporating. However, the barrels' wood eventually stops adding colour, aroma, and flavour to the tequila. When this happens, the barrels are disposed of, and the wood is used for creating crafts and furniture that you can find all over Tequila Jalisco.

tequila cask used in the Scotch whisky industry

Yet again, it is impossible to say at what point the tequila barrel was repurposed for use in the whisky industry. Is it after the first year, second, or, in the worst-case scenario, sold only after the fifth fill when it can no longer be used to make tequila?


Shochu Casks

shochu casks

Image by Denzouingura

Shochu—the most popular domestic spirit in Japan—is an aged spirit distilled from rice, barley, sweet potatoes, buckwheat, or brown sugar. However, it is sometimes produced from other ingredients such as chestnuts, sesame seeds, potatoes, or even carrots.

Although most shochu is aged less than a year in steel tanks, earthenware pots, or bottles, some producers prefer finer tastes collected after three or, on rare occasions, even 20 years of ageing in wood. Some casks are known to have a capacity of 450 litres.

According to Kagura Shuzo: "The shochu taste changes depending on the burned state and the number of the cask usage. To keep the best taste, the inside of the cask is re-burned after three times of use."


Rejuvenated Casks

re-charring casks

Image by Nephin whiskey

On some occasions, barrels that show great potential can be rejuvenated or recharged. During the process, the inside of the barrel is scraped to remove the initially char and re-toasted to reopen the pores of the wood.

Rejuvenated casks may hold two further fillings, after which there is the option of additional rejuvenation, though two treatments are usually the limit.


Thank you for reading The Whisky Ardvark. Please make sure to check out some of our other informative article listed below.


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