It’s important to understand the difference between a selective finish and a selective maturation in the whisky ageing process. When selectively finishing a product, we take a portion of that whisky and fill it into freshly emptied casks, such as ex-tequila barrels or ex-rye casks. Then that blend is monitored regularly to check for flavour development – as each cask is different, they all operate in their own way and it doesn’t take a set amount of time to get to the right level of flavour. It’s a hands-on, bespoke process in the blending room. With a selective maturation, the blend spends its entire maturation time in that cask – so for Chivas Extra 13 Sherry Cask, a portion of our blended Scotch whisky spends all 13 years in first-fill Oloroso sherry casks. When looking at cask finishes, it’s important to consider the history of the cask. When using a cask for a long maturation (such as 15 years or more) a second or third-fill cask allows for fantastic flavour balance between the cask influence and distillate (the whisky spirit prior to maturation) character. If the distillate spends a long period of time in a first-fill cask, the cask influence will be too strong and is likely to take over completely. With younger maturations however, first-fill casks are ideal for bringing through cask flavour quickly.