As most Whisky enthusiasts will know, maturation in oak barrels is perhaps the most important part of the Whisky making process, as this is where the liquid gets the majority of its flavour.
The oak wood imparts lots of different elements that add certain flavours. Barrels used for ageing, especially in Ireland and Scotland, will also more times that not, have held another liquid, typically Bourbon or Sherry.
This adds even more flavour, as the new malt interacts with the remnants of what was in the barrel before.
There are different techniques that also encourage more flavours to come out of the wood. One of the most common is charring.
This caramelises the inside of the barrel, as well as increasing the surface area over which the liquid can interact with the wood, and introducing charcoal, which acts as a purifier and removes certain elements from the Whisky.
In recent decades, it has become more popular for brands to “finish” their malt. But what exactly does this mean, and how does it affect flavour?
What is Cask Finishing?
Cask finishing is essentially moving the malt from one barrel to another, to allow it to finish maturing.
The second barrel will most likely have held something a bit interesting, like red wine, champagne, or even ale, in the hopes that the flavour of this liquid will seep out and improve the malt.
Other common barrels used for finishing include sherry and Bourbon
Where did it come from?
The Balvenie’s Master Distiller David Stewart was using this technique in the 1980s, as were Glenmorangie.
Stewart’s Balvenie Classic, now Balvenie Double Wood, was one of the first Whiskies released that had been created with this method.
It has really taken off in the last 20 years, with some of the more experimental drams coming out in this decade. These include releases such as Glenfiddich’s 21 Year Old GranReserva, made using Caribbean Rum casks, or Teeling’s Stout Cask release.
What does it do to flavour?
The most important thing for distillers is that this technique affects the flavour in a positive way.
It’s all well and good finishing your malt in a champagne cask, but unless that makes it taste better, there’s no point.
Glenfiddich’s Brian Kinsman says, ‘The previous contents are important, but from my perspective it’s because of what it’s done to the oak. The oak is the constant, and the previous contents interact with that oak and remove certain things and add certain things; change the chemistry of the oak.”
The oak of the cask imparts a lot of flavour, and what Kinsman is saying here, is that the flavours from the previous liquid will have their own effect on the oak, which in turn will each have a different effect on the Whisky.
Like with a lot of things in the Whisky making process, it all comes down to the intricate chemistry of how the oak and malt interact.
It cannot be said exactly what effect different liquids will have on the oak and therefore, on the malt, but it is safe to say that cask finishing has been used to produce some pretty impressive malts.
We may as well start with the original. The Balvenie Double Wood 12 Year Old. This malt has been matured in refill American Oak casks and finished in European oak ex-sherry casks. It is full of sweet nuts and dried fruit, with a mouth watering dusting of cinnamon and nutmeg spice. There is also a beautifully sweet vanilla and caramel note on the palate.
Finished in Caribbean Rum casks, the Glenfiddich 21 Gran Reserva is deliciously sweet. It has lots of sugary notes and a wonderful hint of spice. The body is thick and saccharine, with lots of dried fruit and caramel notes. This is like a Christmas cake in a bottle, but with a little bit more heat.
Made in collaboration with Galway Bay Brewery, this malt has been finished in – you guessed it – stout casks! The flavours are rich and deep, with lots of chocolate and vanilla. The palate is fruity but sweet, with oranges, caramel and a lovely malty flavour coming through.
TeLasanta has been matured in American White Oak ex-Bourbon casks and finished in Oloroso and Pedro Ximenez Sherry casks for two years. it is full of sherry flavours such as cinnamon and vanilla, with a lovely note of oranges and caramel on the palate.
This malt has been finished for 12 months, in 228 litre Burgundy Wine casks from Chateau de ChassagneMontrachet in France. There are lots of berries and nuts, and sweet vanilla notes. It finishes with a spicy kick and some lovely citrus fruit tones.