Why wine casks and whisky are a match made in flavour heaven

Wooden casks have a long history of making drinks great. The Celts and Gauls were using them way back in 3rd century BC because clay pots just weren’t cutting it anymore. Then the Romans used them to transport wine around the empire. Wood was plentiful, easy to shape, and, at least most of the time, provided a watertight solution.

And therein lies the magic. Casks are watertight, but they’re not airtight. While they safely (you’d hope) hold your wine, beer, whisky, or whatever, they ‘breathe’ with atmospheric conditions like temperature and humidity. This ‘breathing’ lets oxygen in and out of the barrel. It also draws the contents of the cask into the wooden staves. This means that even if you tip that barrel out, some of its contents will remain in the oak staves. It’s magical.

What’s even more enchanting are the interactions that happen between the liquid and the oak during this process. The liquid takes on colour, flavour and aroma compounds from the cask. The cask extracts harshness from the liquid. It’s transformative. And, in the case of whisky, it informs the very character of the spirit – even if it’s a brand-new barrel being used for the first time.

Now we understand the basics of maturation, it’s easy to see why what a cask was used for before is so important to a whisky-maker now. Bourbon casks will typically impart vanilla, coconut and citrus notes – the aromas and flavours common in bourbon. Sherry casks will be about dried fruits, nuttiness and dark chocolate. Rum casks might contribute tropical fruit notes. Tequila casks a peppery, leafy element. Wine casks? There’s so much potential.

Think of your favourite wines. Perhaps a Merlot or Cabernet Sauvignon from Bordeaux. Use casks that previously held these wines in whisky-making and you’ll likely get cherry and red berry notes as a result. What about a Sauvignon Blanc white wine? Expect notes of green apple or citrus peels. Now extrapolate that out and think of the flavours distilleries could tap into using Argentinian Malbec, buttery Chardonnay, or even Champagne casks. It’s deliciously mesmerising.