Refill

With the exception of the US, the majority of cooperage in the whisky industry comprises reused bourbon or sherry casks. The initial use of these casks by distillers is generally referred to as a "first-fill" or "fresh" cask, whereas each subsequent use sees it referred to as "refill."

With refill casks having been used to age whisky before, they tend to impart less flavour from the wood and as such are preferred by distillers wishing to showcase the character of their spirit. Being less active, refill casks will also mature whisky more slowly and by breathing less, will result in a far lower angels' share than a first-fill alternative. This makes refill wood particularly suited to long maturations of 18 years and over.

This is not to say that the wood is without continued influence however, and the whisky held in the cask previously can often impart new flavour on the new habitant liquid. As distillers have experimented with maturation over the years, refill casks that previously held big flavour whiskies such as heavily peated single malt have become increasingly popular.

The nature of refill casks means that they can be of any size, however the majority come in the shape of 250 litre hogsheads and 400 litre butts.