The maturation period of whiskey, which involves aging the liquor in wooden barrels, is one of the most interesting stages of the whiskey production process.
The process allows the whiskey to interact with the oak barrels to arrive at the desired state in line with the particular distillery. The type of barrel used for maturation is usually determined by the Master Blender who seeks to achieve a particular character and maintain the style of the whiskey that the house is known for.
What is aging?
Aging refers to the process of storing distilled spirits (or wines) in barrels for a specific period of time. The time may take up to 10 years, 20 years or even more. The aim is usually to extract harsh flavours from the raw alcohol while distinct characteristics are added to it from the barrel’s wood.
Why age whiskey in barrels?
For those who are whiskey aficionados, the answer to this is as familiar as their own names. However, for the spirit drinkers who are new to the world of whiskey, the question begs a comprehensive answer.
What to know about barrel aging for whiskey
Oak Barrels are used
This is about the first thing anyone should know about the maturation of whiskeys. Oak barrels are used because of their distinct physical and chemical nature. Because oak is pure wood, it is preferable to other types of woods like rubber or pine.
The oak adds taste and aroma to the spirit, while also extracting undesirable elements from it. It also interacts with the spirit, adding extractive wood elements as well as giving it the desired colour throughout the aging period.
There is a Toasting or Charring
When the barrels have been created, the whiskey is not just poured inside. Traditionally, the barrels are either toasted or charred when they are built, this creates a layer of charcoal that filters out unwanted flavours from the raw spirit. Bourbon casks are usually charred, while sherry casks are toasted.
Colour comes from the barrels
Whiskey would be a clear spirit just like gin and vodka if they were not aged in oak barrels. It is the barrels that give it colour. As the spirit interacts with the barrel, the colour of the wood is extracted and blends itself into it, giving it the amber or golden brown colour. The longer the spirit is aged, the darker the colour. Moonshine is the only clear whiskey because it is unaged.
The Barrel adds flavour too
More than just the colour, the barrel also adds flavour to the spirit too. How does this happen? The barrel actually mellows out any harsh notes found in the raw spirit through absorption. So when you see whiskey notes with ‘oakiness’ or ‘undertones of charred oak,’ then know that it is referring to the flavours gotten from the oak barrels. Depending on the species of oak used in the barrel, different flavours can be gotten.
Quercus Alba, “White Oak” (American Oak), Quercus Petraea, “Sessile Oak” (Europe) and Quercus Robur, “Pedunculate Oak” (Europe) are three most used species of oak.