Because we’ve used a “first fill” bourbon cask, let’s have a look at how this affects the taste and nose of our whisky.
First off the American white oak used contains very few tannins. This creates a more mellow and smoother tasting whisky.
Next, the barrel has been “toasted”. This is a heat treatment that transforms the interior of the wooden staves (as opposed to the interior of the barrel), heating it to 150ºC (300°F) and in the process caramelises the wood sugars. This is where the vanilla and caramel flavours and colours come from in our whisky.
Finally, the barrel is charred. By burning the inside of the barrel and then extinguishing it quickly with water, this creates a thin layer of charcoal. This charcoal is used for a process called “subtractive maturation” which removes many of the sharp and intense tasting sulphur compounds and boosting the ester notes in our whisky. Obviously, this charcoal has already been used once in the maturation of the original bourbon and won’t last forever so it’s important to use a first fill cask like ours to get the most benefit.