Why do we burn the inside of our whisky casks?

Malin Åberg

Why are the inside of spirit casks toasted /charred before they are filled – and how does that influence the drink’s taste? Mackmyra’s Master Blender Angela D’Orazio provides the answer.

“The casks are charred either industrially in large ovens, where after being assembled they are treated on the inside and sealed together with large flames, or as smaller, handcrafted versions such as those made at Varalövs Tunnfabrik, which involves a similar process but on a smaller scale, with manual sealing using fire baskets placed inside the casks or small manual joins.
The degree of charring that Mackmyra uses is the second highest level, where the crocodile skin appears on the cask but does not have 100% coverage.”

“In the case of a high level of charring, the cracks in the crocodile skin make it easier for the whisky to permeate into the oak barrel – and the different levels of charring have different chemical effects that give different tastes in the final product. High levels of charring also give rise to the pleasant caramelised vanilla tone that we like in the whisky.”

/ Malin Åberg, Mackmyra Whisky