Why finish whisky in different barrels?

Why finish whisky in different barrels?

To quote Stephanie Macleod, our Master Blender: “Whisky is MAGICAL when it interacts with wood, the two elements were made for one another”. Oak ageing is definitely an essential part of the whisky production process, evidenced if you have ever tried new make spirit. That said, it saddens me that so many experts throw around the statistic that 70% of the flavour comes from the barrel. In this article I want to explore what the cask does, particularly in the context of ‘finishing’ where we use as particularly distinctive barrel to add even more flavour.

I work in a distillery, so I am slightly biased that the distillery style in the new make spirit is essential to the final flavour of the whisky. Of course, the casks add a lot to the character, but our team work with genuine care to maintain the flavour of our new make spirit. If the cask was everything, then why would they bother?

The first step to understanding a finished whisky is to taste something from the distillery that has minimal cask influence. Then you can understand what the finishing barrel has added. Try to find something matured in bourbon, preferably refill casks that have given up a lot of their character previously. Aberfeldy 12 uses a range of new and old cask types, bourbon and sherry, but is a great representation of the distillery style, or you could try our triple tasting pack to see how it evolves with age. These kinds of vertical tastings are great fun.

Once you understand what the ‘regular’ style is like, it is useful to have a basic understanding on what happens in the cask during maturation, it is far more than just adding oak flavour.

New make spirit comes off the stills packed with flavour, so much so it is hard to identify them. Distillation doesn’t just raise the abv, it also selects and concentrates flavours. In the barrel, this level of concentration is softened so the individual notes can be enjoyed. The char on the inside of the barrel helps this, alongside gentle oxidisation and evaporation of alcohol to soften everything up. Oak is the wood of choice for the maturation of Scotch Whisky because it allows the spirit to breathe.

Oxidisation also creates a fascinating array of new flavours. These don’t come from the wood but from air that seeps in through the oak. The process happens faster for wine and that is why you can literally taste it happening as you decant or swirl a glass of wine. The effect is more subtle with spirits, but that makes it all the more elegant.

The final thing that happens during oak maturation is that ‘stuff’ moves from the wood into the spirit. This obviously includes flavour, but also colour (all spirits are clear when they come off the stills), and things like tannin (giving a dry, chalky feeling inside your cheeks). This is where that quote about 70% of the flavour from the barrel comes from. There is undoubtedly a very different flavour after 12 years in casks, but not all the flavour comes direct from the wood. Otherwise we could put vodka in a barrel and get a characterful spirit!

I'm not going to go into all the types of cask flavour in this article but focus on the red wine barrels that are chosen for the annual Aberfeldy special editions. You don't see red wine used to finish whisky often, because it is really difficult to get right. Stephanie and her team have a real flair for it. I started my career in the wine industry and red wine is a very worthy cask choice. As I have already alluded to with oxidisation, wine develops flavours more quickly and the variations are easier to spot. I can taste a Chablis and tell you which part of the region it was made. I can't taste a whisky and tell you where the barley came from! That subtle flavour variation is transferred to the whisky.

The latest wine casks are both Cabernet Sauvignon dominant. However, they have wildly different styles because of the climate the grapes were matured in and the way the winemaker has treated them. When they arrived, we did staff training to ensure everyone was comfortable with the differences (what a perk of the job alongside working with me!!!). It was a nerve-wracking moment seeing if the difference would be obvious, but we shouldn't have worried. As you'll see from my tasting notes, the 15 year old Napa is ripe, juicy, jammy, with mint and violet. The 18 year old Tuscan has cherry, chocolate and more savoury herbal notes.

Two fantastic extensions of the Aberfeldy style, hopefully you appreciate them more if you understand where the flavours have come from.

Author: Jonathan Wilson, Visitor Operations Manager

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