What comes from Pot Stills is not whisky. In fact it is called New Make Spirit (NMS), a colorless liquid which contains around 30% of the character of the final product. NMS is the DNA or blood line of any Single Malt Whisky as every bottled variant from one distillery will share the same NMS. It is then how you mature it that gives you an expression. The creation of NMS is the science of whisky making, as it needs to be the same every time to ensure congruence in flavor. The Glenlivet distillery, for example, has not changed the way in which it has made its New Make Spirit since its beginning in 1824, nearly 200 years ago!
Once distilled, the spirit is then introduced to Oak casks and this is where we discover the art of making Scotch Whisky.
Where did the ageing of Whisky begin?
Ageing of whisky came around with a bit of luck. It was first documented in the late 15th century, but up until then illicit whisky distillers would transport their clear spirit in anything that they could and would often just drink the clear liquid straight from the stills.
Once the popularity of whisky started to increase and gained its new-found legal standing, more official ways of transporting the liquid were needed. Keeping in mind how they had been used for thousands of years, wooden casks were an obvious choice. As these casks travelled increasingly further distances, the recipients found that the color and flavor of the liquid had changed, and for the better!
This led to a huge increase in demand for wooden casks and the wood of choice became Oak due to the desirable flavors and characteristics it gave the whisky. However, sourcing oak became difficult in the UK as the British Navy were becoming rather successful in their global conquest and required Oak (and lots of it) to build their ships. For a while, Scottish Distillers were at loss, production was slowed, until someone came up with a clever solution. At the time, Britain was importing large quantities of Sherries, Ports and Wines, so the innovative Scots started to transport these second-hand casks back to their distilleries to start ageing their whisky. This ingenious idea led to a smoother liquid and imparted sweeter and more robust flavors from the previously held alcoholic liquids.
How does the cask age the liquid inside?
Casks are made from wood and this means it is porous, which allows the movement of air in and out which means that the cask is effectively breathing. This breathing allows the naturally occurring chemicals in the wood to marry with the whisky inside the cask, for example, Cinnamaldyde is the compound that gives us a cinnamon note in the whisky and Vanillin, as the name suggests gives us, vanilla notes. Different casks and their previous use will be more likely to produce certain flavors, and when we start ageing our NMS in casks, our master distillers will have a clear idea of what flavors they want to achieve.
These compounds that provide flavor in the cask are so delicate and intricate that it becomes extremely complex to manage one cask, let alone the marriage of two or more.
Cask size plays a major part in whisky maturation. They come in a variety of shapes and all have a unique name. The most common are Bourbon Barrels at 200 liters, Sherry Butts (500 liters), Port Pipes (550 liters) and Hogsheads (250 liters). However, Scotch whisky distilleries also use a number of other casks in their maturation. The most common casks used in whisky maturation are ex-bourbon casks and ex-sherry casks, with each cask offering their own unique characteristics to the whisky. The ‘ex’ prefix refers to the fact that the cask previously held bourbon or sherry. Ex-bourbon casks offer traditional notes of apples, vanilla and coconut whereas ex-sherry casks offer notes of raisins, syrups and spices. Beyond these notes, there is a plethora of aromas and flavors that can be produced from any cask used in whisky maturation.
Master Distillers across Scotland train for years to develop a deep understanding of how different casks curate different aromas and notes; and when we start discussing all the wonderful ways in which we can finish our whiskies, the flavors can become wonderfully more complex. For example, The Glenlivet Nàdurra series introduces a peated cask finish which takes a cask that previously held peated whisky and introduces non-peated, aged The Glenlivet to it. This process imparts a delicate aroma of peat smoke rather than dominating the delicate bourbon barrel notes.
Another example of a unique form of maturation is ‘double-cask maturation’ like that from the Aberlour distillery. Aberlour 12-year-old, for example, is aged for a minimum period of 12 years in traditional oak casks and sherry oak casks separately. These are then married, giving the whisky a depth of character with spice and rounded fruitiness.
These are only a few reasons that I refer to ‘the maturation process’ as the artistry of whisky making. It takes more than just decades of experience, it takes instincts, ancient workmanship and a bit of luck to come to what we know today as Scotch Whisky.
So, the next time you go to select your whisky, take into consideration, not just the skill that has gone into it but the true discernment, patience and love.
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