Hogshead: Understanding How Scots Use Whisky Barrels

By Lindsay Brandon / March 7, 2016

Cooperage, or the art of cask making, comes in many forms, all of which are celebrated in the maturation of Scotch. Each name of the ‘cask’ or ‘barrel,’ as we broadly refer to the cylindrical wooden containers here in the U.S., is actually indicative of its liquid capacity.

A barrel is not simply of a wooden spirit aging vestibule, but rather a specific size, which can include: 36 Imperial gallons, to be precise (an Imperial gallon is about 1.2 American gallons). Comparatively, the ‘Firkin’ is nine Imperial gallons, the ‘Kilderkin’ is 18 Imperial gallons, the ‘Hogshead’ is 54 Imperial gallons, the ‘Sherry Butt’ is 108 Imperial gallons, the ‘Madeira Drum’ and the ‘Port Pipe’ are 143 Imperial gallons, and the ‘Tun’ is 216 Imperial gallons.


A hogshead cask (left) compared to a bourbon barrel (right) Image courtesy of Speyside Cooperage Kentucky.

Regardless of their size, the Scots prefer aging in oak because it is the only wood that prevents seepage while still allowing the contents to breathe due to its ideal cellular structure. It certainly isn’t cheap or easy: the ideal sourced oak is between 100-150 years old, and depending on the specifications for each cask, the oak is usually laid out to weather for around three years in order to rid the wood of bitter tannins before it even makes it to the cooper.

At the Speyside Cooperage, for example, they’ve been making and repairing oak casks since 1947 in more or less the same fashion that coopers have for the past 5,000 years. The largest independent cooperage in the U.K., Speyside, also has branches in Ohio and Kentucky, and often trades casks with other business.

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In the world of Scotch, it’s very common for coopers to break down five ex-bourbon barrels into staves and reassemble them with new ends to make a hogshead, or ‘hoggie.’ Considered the most popular aging mechanism, it allows for more whisky to be stored in the same amount of warehouse space, although some say it is simply better to age scotch in larger casks.

Bourbon casks are charred on the inside to various levels, depending on the flavor the distiller wants to impart during aging. Caramelization of the sugars in the oak created during heavy charring (required for bourbon barrels) are what impart the traditional vanilla and caramel flavors American whiskey drinkers love. The initial char and size of the cask also have a pronounced impact on the character of any Scotch whisky aged inside – and many Scottish distillers err on the side of caution when it comes to imparting a Bourbon-like flavor profile.

Flavorful ex-bourbon casks are often converted to hogsheads, which have a greater volume-to-surface area ratio that tempers the impact of the heavy char. Lagavulin, for instance, uses hogsheads to house their older cask spirits so the spirit can age for a longer period of time without taking on too much flavor.

When it became more difficult to source sherry casks during the Spanish civil war in the late 1930s, use of bourbon casks became much more common. Nowadays, somewhere between 300 and 400 thousand bourbon barrels are shipped to Scotland for second use, compared to somewhere around 18,000 sherry casks.

A little over 90% of the 8.5 million casks in Diageo’s inventory in Scotland are ex-bourbon or rye American Oak. At Bruichladdich, their figure is closer to 97%.

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The stability of bourbon production in the U.S. means that second-use American oak is sure to remain a prime choice for Scotch distillers, regardless of whether they keep the barrel or turn it into a “hoggie.”