BackA journey of barrels
Whiskies from most countries are matured in two main types of casks: ex-bourbon barrels and ex-sherry barrels
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The world of whisky is expanding by the day, with new distilleries opening in every country you could imagine. However, they don’t all start off by making whisky. The process of producing any aged spirit, from brandy to rum to whisky, is an expensive one.
There are raw ingredients, energy, manpower, casks and maturation facilities that need to be taken care of, and then there is the most expensive of all the commodities: time.
But despite the fact that new countries are producing whisky, there are three key nations that underpin the very foundation of whisky-making: Scotland, Ireland and the US.
For a writer who is based in London, the first two of these countries are just a spittoon’s distance away and regular readers of this column will know that I visit these hubs on almost a weekly basis.
America, however, is not so close.
Currently experiencing an explosion of craft distilling, fuelled by the success of craft beers and licensing laws that are conducive to investment in small-still production, this boom in the US has seen many individuals set up and start spirit production, helped by a wealth of natural resources and a history rich in distilled spirits. And this is exactly where bourbon comes in, to kick-start the rest of the world’s whisky.
Bourbon whiskey is one of America’s most famous products, up there alongside blue jeans, apple pie and Hollywood movies. Predominantly, but not exclusively produced in the state of Kentucky, bourbon whiskey has a long journey that often ends with distillers in Scotland, Ireland or Japan.
It is no secret that whiskies from these countries are matured in two main types of casks: ex-bourbon barrels and ex-sherry barrels. On a recent trip to Jerez, Spain, which I spoke about in this space around the start of the year, I was introduced to the highlights of cask production, Spanish-style. I also learnt how they use a mixture of European oak and American white oak for the casks in which sherry is matured.
Soon after that trip, I had decided that I needed to check out the opposition. So I jumped on a plane to the US to see how barrel production was taken care over there.
The American way of cask production differs slightly from that of the Europeans. In Jerez, casks are made big (500-litre capacity) and can be made from either American or European oak. In the cooperages of the US, however, casks are called ‘‘barrels", are smaller at just 200 litres, and are always made from 100% American white oak.
These two types of seasoning, either with bourbon or fortified wine, are hugely important to the resulting whisky in your glass. Let’s have a look at their distinct flavours.
Ex-bourbon barrel:
With an average size of 200 litres, these are made from American white oak, sourced from the central belt of the US. When produced for bourbon distillers, these casks are brand new and have been lightly toasted over an open fire. This gives the mature bourbon a huge hit of sweetness and vanilla from the tannins and vanillins hidden inside the oak.
Once they have held the American bourbon, usually for around six-eight years or sometimes longer, they are returned to the cooperage to be re-toasted and sent to Scotland, Ireland, Japan and other whisky-producing nations.
Here, these casks are often re-coopered into hogsheads, which are slightly larger versions of the same casks, but with 50 litres added capacity.
The flavours that come from a used bourbon barrel, or a ‘‘First Fill" cask as it is often referred to, are similar to those that one can find in a bourbon whiskey, but much less intense: delicate vanilla, some white chocolate and occasionally white flowers.
Ex-sherry oak barrel:
These are much bigger in volume than the bourbon barrels, holding around 500 litres. The style of sherry is also important, with lighter styles (which most sherry casks will be) giving tropical fruit flavours to the maturing whisky, while heavier styles such as Oloroso or Pedro Ximénez delivering rich fruit jams, big red berries and red flowers and sometimes cinnamon spices.
Usually, anything labelled as an ex-European oak cask would have held sherry, but port or other wines are also used for seasoning. This will be mentioned if so.
About 90% of all Scotch whisky is matured in ex-bourbon whiskey barrels, as the intense flavours delivered by sherry or port casks can be so heavy that only a few of these casks are required in an overall stock portfolio.
Both American and European casks can be used more than once, but with every use, less character is left for the next batch of whisky.
Any whisky, from single malts such as Glenfiddich or The Macallan, through to blends such as Johnnie Walker and Chivas Regal, or Japanese and Irish whiskies, will usually be made of a mixture of liquid from all these casks, to give their final product the balance that it needs and to keep the quality at the highest possible levels. Single malts will often detail on their labels what type of casks have been used to construct the product.
Take a look next time you’re buying a whisky and maybe you can go on your own little Transatlantic journey.
Joel Harrison is a drinks writer and consultant and co-founder of the website Caskstrength.net.
Read all of Joel earlier columns
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