The most important part of the taste and refinement of a bottle of whisky is something that you can barely see from the bottle itself but instead comes from the vast casks that are owned, filled with spirits and generate these most critical characteristics through time and refinement.

There are a lot of different types of wood used to make these barrels, often with varying shapes, sizes and qualities attached to them. 

However, whilst these casks can come from anywhere and theoretically be made from any oak wood to qualify as Scotch whisky, as long as it has also been distilled and matured for at least three years and a day in Scotland, a lot of the barrels themselves come from far further adrift.

This has had a massive effect on standardisation; most whisky casks that a person is likely to have access to and own will be 200 litres (44 imperial gallons or 53 American gallons), and when people in the know talk about a barrel of whisky, they are talking about a specific measurement.

Why is this the case? Why are American oak barrels so commonly used for whisky? There are a few reasons, but one of the biggest is some rather unusual, contradictory legislation.

The Churn Of Barrels

The vast majority of popular United States whisky types are defined legally as “straight whiskey”. This includes rye, bourbon, malt or wheat, and there are strict rules for the types of casks they can be aged in.

Unlike any other country in the world, straight whisky in the United States must be stored in new, charred oak containers, which is unusual given that a lot of the character of particular whiskeys not only comes from the grain but also from the cask used.

However, because of this legal requirement, barrels of straight whisky (which is effectively every whisky that is not blended or corn whisky) cannot be reused after they have been decanted. 

One option is to dismantle them entirely and use the wood and metal bands for something else, but the barrels themselves have value to whisky traditions around the world, and so they are often sold to distillers around the world.

This, inevitably, has a tremendous effect on standards and conventions throughout the world whisky trade. Many whiskeys are stored in American Standard Barrels (ASB) because they are the most affordable option, if only because American distillers have few alternatives.

It also forms the foundation of the hogshead, a larger cask made by breaking down five ASBs into four hogshead barrels.

These barrels are then used once for premium single malt whiskies before being reused multiple times for mass-market blends or for other spirits, which in turn sometimes leads to them being used for finishing.

Ultimately, all of this proves that the whisky industry is largely symbiotic. Whilst there are obviously national traditions, flavours and cultural differences, there is a lot of trading of ideas and indeed barrels that contribute to the final, incredible spirits we enjoy.