Whisky Barrels Are The Key
To impart flavour and colour into your favourite single malt all Scotch whisky is matured in oak casks. These casks are mainly sourced from the United States, Spain or Portugal. These oak casks are often called barrels, hogsheads, puncheons or butts.
The casks from the United States have previously predominately been used for the maturation of bourbon whiskey, the casks from Spain to mature Sherry and the casks from Portugal to mature Port.
Scottish law states that whisky barrels can be used as many times as desired however in the United States casks are only allowed to be used once. This means that supply to the Scottish whisky industry is in good supply, as long as the world continues to drink bourbon. In Spain Sherry barrels can be used over long periods of time allowing the barrels used to soak the Sherry flavours into the wood. Supply of Sherry barrels is important however in recent times drinking Sherry has become less desirable and the barrels are now becoming more scarce and expensive. This then creates a upward price movement in whisky which has been matured in a Sherry barrels. The same situation also sits with the barrels sourced from Portugal which contained Port.
The biggest challenge a distiller has is sourcing, choosing, purchasing and crafting the perfect barrel.
The casks purchased are various sizes and impart different flavours into the spirit. Barrels range from a 45 litres Quarter Cask to a large 650 litre Madeira Drum. Lets take a look at each of the casks in details and match them with some of our favourite whiskies.
Bourbon Barrel (approx. 180 litres to 200 litres)
Previously used to mature bourbon from the United States these barrels are one of the most common used in the industry This is a standard bourbon barrel and can only be used once in the production of bourbon whiskey. They required by law to be made from American oak. Fact: Moet Hennessey own their own forest in the United States where they grow American oak trees. They select the right trees at the right time to be cut down and used in the maturation of bourbon. Giving the barrels to the American bourbon industry ‘on loan’ for ‘seasoning’. This gives them control over the barrels from tree to bottling.
Your favourite whisky: Arran, The Balvenie, The Glenlivet, Glenmorangie, Jack Ryan, Auchentoshan, Glencadam, Tomintoul and Signatory Vintage.
Purchase whiskies matured in a bourbon barrel here
Hogshead Barrel (approx. 225 litres to 250 litres)
After bourbon barrels, hogsheads are the second-most common type of cask used in maturing Scotch whisky. This barrel is made from American oak and most commonly built from the staves of bourbon barrels. Hogsheads are used to mature whisky for longer periods as the spirit to wood contact is reduced due to the larger size of cask. It is possible to have a whisky matured in an ex-Bourbon hogshead and an ex-Sherry Hogshead however Hogsheads are used to mature many other spirits and beverages. Fact: A tobacco hogshead was used in British and American colonial times to transport and store tobacco. It was a very large wooden barrel. A standardised hogshead measured 48 inches (1,219 mm) long and 30 inches (762 mm) in diameter at the head (at least 550 L or 121 imp gal or 145 US gal, depending on the width in the middle). Fully packed with tobacco, it weighed about 1,000 pounds (454 kg).
Your favourite whisky: Glenfiddich, Dalwhinnie, The Balvenie, The Glenlivet, Tomatin, Glen Grant, Tomintoul, Glencadam and Signatory Vintage.
Purchase whiskies matured in a hogshead barrel here
Sherry Butt (approx. 475 litres to 500 litres)
The Sherry industry generally use a barrel or cask called a butt. This is the second most commonly used barrel in the maturation of Scotch whisky. These butt’s can be made of Spanish oak or American oak, both oaks contributing different flavours to the spirit. Fact: In 1981, the Spanish government changed its export rules, banning the use of casks for shipping. The global supply of sherry barrels dried up overnight.
Your favourite whisky: Edradour, GlenDronach, The Macallan, Ben Nevis, Dalmore, Springbank, Glengoyne, Benromach and Signatory Vintage.
Purchase whiskies matured in a Sherry butt here
Quarter Cask (approx. 45 litres to 50 litres)
With a higher ratio of wood to liquid than other casks these barrels accelerate the maturation process. This can however impart a very strong oak flavour into the spirit so it is usually used for finishing a whisky or with spirit that is very robust in flavour. These cask are quarter the size of a Bourbon barrel. Fact: These casks can also be referred to as Firkin, Rundlet, Kilderkin. They are featured in most early Lark whisky maturations.
Your favourite whisky: Limeburners, Lark, Laphroaig, Springbank, Longrow, Hazelburn, Kilchoman and The Balvenie.
Barrique (approx. 250 litres to 300 litres)
Described as slightly larger hogshead barrel and used most commonly in the wine industry. Innovation in the Scotch whisky industry has seen barriques being used more commonly in recent years. Fact: Kavalan Vihno Barrique from Taiwan won the ‘World’s Best Whisky Award’ in 2015 using barriques used in the California wine industry.
Your favourite whisky: Bladnoch, Signatory Vintage, Kavalan.
Puncheon (approx. 450-500 litres| ~286-350 LPA): After butts, puncheons are the second-most common type of casks used to mature sherry. Dumpier than a butt, these are generally made with Spanish oak staves. Machine puncheons are made from American white oak and generally used in the rum industry. While machine puncheons are still rarely used for maturing Scotch, they have become more common in recent years.
Port pipe (approx. 550-650 litres | ~350-455 LPA): Port pipes are the industry standard cask for maturing port wine. Port pipes are long and similar in proportion to sherry butts, although their width is close to an ASB. Port pipes are generally only used to ‘finish’ Scotch whiskies for a final few years.
Madeira drum (approx. 600-650 litres | ~381-455 LPA): Like sherry butts and port pipes, Madeira drums are the industry standard for maturing Madeira wine. However, Madeira drums are significantly squatter than these counterparts, and are built from thick French oak staves. Madeira drums are relatively uncommon for maturing Scotch whisky and are generally used to ‘finish’ aged stocks.
Casks can be described as ‘first fill’ or ‘refill’. An American whiskey cask or barrel that is being used to mature Scotch for the first time is referred to as ‘first fill’. It becomes a ‘refill’ cask when used for a second or subsequent time. ‘First fill’ casks are more active in the maturation process of Scotch, imparting stronger flavours to the whisky from the oak and the previous contents of the barrel. ‘Refill’ barrels, by contrast, are usually less active in maturing Scotch, allowing the spirit to dominate the maturation process. It is the job of a good cooper to maintain the casks well to extend their useful life, and to ensure they continue to mature the whisky to the right quality standards.
The casks are stacked either three high in traditional ‘dunnage’ warehouses or more commonly now in modern palletised warehouses. The key is to allow lots of cool, damp, Scottish air to circulate.
All casks are porous, allowing the spirit to evaporate which is necessary for maturation. A small number of casks may leak, and lose more whisky than they should in the first year. In modern warehouses leaky casks are usually left where they are, because moving them around to sort out a leaky one costs almost as much as a cask of newly made spirit is worth, and risks damaging others in the process.
Losses from evaporation and leakage amount to around 2% per year, with an extra 3% lost on filling as spirit is absorbed by the wood. This is known as ‘in-drink’.
Good casks, well cared for, can last for up to 50 years or longer.
Explore the casks used and purchase from your favourite casks. Click here
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