An aging process used in the production of whisky following the process of distillation in which the distilled spirit is placed in wooden casks for long periods of time. There is a legal requirement to mature Scotch whisky for a minimum of three years and it is often much longer. During this time flavours from the casks that have been previously used in the wine, sherry, cognac, and port industries are imparted, and include lignin and vanillin from the wood. The aging process also imparts colour. Around 2 per cent is lost each year through evaporation known as the angel’s share.