If you spend any time reading about whisky then you almost certainly would have noticed the term cask and barrel used interchangeably. I decided to research this and find out if there is an official difference between the words cask and barrel when used in relation to whisky production.
The answer is no, there is no real tangible difference between a cask and a barrel and the words can be used interchangeably. In fact, the definition of the word cask actually refers to a large barrel used for the storage of liquid.
Definition of a Barrel
The word barrel, in relation to whisky and according to several different dictionary definitions basically means the following
A wooden cylindrical container that is greater in length than width and made from staves which are kept in place with metal hoops. Both ends are usually the same diameter
There are several theories as to where the word originated from but it’s generally accepted that it originally came from the Anglo-Norman word Baril. It could possibly pre-date this as barrels have shown up in paintings as far back as Egyptian times which indicates the design is at least 2600 years old!
It is thought that barrels from this long ago would contain corn and not necessarily liquids or alcohol. Many ancient civilisations have made use of barrels to store their sports with the Romans well versed in building barrels by a dedicated tradesman known as a cooper. Interestingly, we still refer to the ancient art of barrel making and restoration by the same term and I recently posted an article you may find interesting on my visit to the Speyside Cooperage where bourbon barrels are restored for the scotch whisky industry.
Out of interest, I had a quick look at the Latin word for barrel to see if it would hold any further clues. A quick search reveals that the Latin word was ‘Dolio’ and translations include butt, barrel, dolium, cask and a very large jar!
Definition of a cask
After researching the word ‘cask’ it is interesting to note that most definitions include the word barrel whereas definitions for barrel do not include the word cask. This does seem to indicate hierarchy in the terms but it’s still not totally clear. I would define the word ‘cask’ as the following
A barrel-shaped container which is usually large, made of staves and hoops and used for storing liquid
As with the word barrel, the origination of the term is largely uncertain however it can be traced back to the 15th century to the Middle-French term casque.
The Romans favoured pottery for storing things, this is well known and we still have plenty of examples of preserved roman pots. It was thought around this time that the switch from pottery to wooden casks was made as there are references from classical writers to wooden storage containers with a hoop.
Barrel size chart
As we have established, there is no real difference between the two in terms of definition. However, there is a difference when thinking about the quantity they are capable of holding. In general, a cask could represent any of the different sized containers but a barrel has a very specific size.
I have put together a simple table below which demonstrates some of the most common cask sizes used in whisky production.
Cask and barrels used in Scotch Whisky production
The majority of Scotch Whisky producers use American oak barrels to mature their whisky. This is simply due to the abundant supply coming directly from the American Bourbon producers. The Bourbon distillers use their barrels a single time whereas distillers in Scotland will use barrels for maturation multiple times. In between each cycle, the barrels are inspected to see how far the liquid has been absorbed into the wooden staves. Eventually, when the liquid has almost penetrated right the way through, the barrels will be discarded as they no longer impart any flavour. Up until this point, the barrels will be repaired by the coopers between each use cycle.
Interestingly, the use of oak barrels in whisky production is a legal requirement which is generally accepted around the world. Without the use of these barrels, the new make spirit would resemble something like vodka, nothing like the colours and flavours we have come to expect in whisky!
In the 1500s the Scots began to develop a passion for sherry which has continued to grow ever since. In the 1800s, as Scotch whisky began to grow in popularity, there was a choice between sherry and rum casks freely available to reuse for whisky maturation. The wood used in these barrels was made from European Oak. Sherry became the most popular between the two and much of the early whisky manufactured was matured in these sherry barrels. Some distilleries, like The Glendronach, focus solely on maturation in sherry casks. As the Scottish highlands are comprised of rolling hills and little in the way of forestry, they have never had the option to build their own casks!
The majority, probably over 95%, of the Scotch whisky production is matured in American Oak. These casks are responsible for many of the flavours detected in whiskies such as vanillas, cherry’s, pine and chocolates to name a few. I have covered this before, but as the whisky industry grows the supply of American Oak may well become an issue. The trees can take over 100 years to grow and not all species are suitable for whisky production. As the supply become limited and the costs go up we will likely see the distilleries in Scotland using more and more sherried barrels over time.
The use of wooden barrels or casks in whisky production is vital as distillers rely on these casks to impart flavours many of us enjoy in our favourite single malts. Wood makes the perfect vessel for maturation as the liquid is prevented from leaking out but the wood is able to breathe taking oxygen in and out depending on the ambient temperature. I don’t think any other property in the modern world could offer a suitable replacement.