01 May 2019
The idea of creating Scottish oak casks has been in my mind for years, first sparked by a walk through my local forest on the Black Isle. During my years in the whisky industry, I visited sawmills in the Highlands and began doing my own small-scale trials at home to find a way to make this idea a reality.
Scottish oak has not been widely used to make casks for maturing whisky. It rarely yields the knot-free wood required for making staves for casks and can be expensive to use. However, an important part of The Whisky Works was developing a long-term, sustainable approach to sourcing and utilising Scottish oak. Our collaborative partnerships with forest owners, sawmills and cooperages has enabled us to get closer to this part of the whisky-making process.
There are two main species of oak native to Scotland – the pendunculate oak, known in Latin as Quercus robur, and the sessile oak, called Quercus petraea. The two trees we used to make the single King of Trees cask were wind-felled on an ancient Highland estate and taken to a local sawmill to be milled into timber planks. The wood is then seasoned, or dried, either naturally in the open air or using a kiln. This helps to achieve balanced moisture levels in the wood to make it easier to work with when constructing the staves for the cask and building the cask itself. Natural air seasoning also helps develop the flavour characteristics in the oak which will influence the whisky itself. The wood used for the King of Trees cask was naturally air seasoned for 3-4 years.
After trailing different toasting and charring levels with other casks, I decided to toast the King of Trees cask over a traditional brazier at 220 degress for 47 minutes to achieve the sweet toasty and soft spice character. The Scottish oak cask has had a huge influence in accentuating the fresh orchard fruit flavours from the malts and the resulting whisky is the epitome of a Highland style – fresh with crisp apples and pears, soft wood spice and cinnamon.
To ensure we are sourcing oak responsibly, we have recently joined a charity which works to restore and expand the native Caledonian Forest and conserve wildlife habitats through a tree replanting programme.
The use of Scottish oak has been a great journey and I’ve enjoyed working together with people from the forest through the milling and coopering process. It’s been many years in the development with lots of muddy boots and splinters along the way.