Single malt whisky (and sometimes a third) time. The final spirit, called "new make spirit", generally has an alcohol content of 60 to 70%. Most new-make malt whisky is diluted to about 62.5% a.b.v. before it is placed in casks to mature. The "new-make spirit", or unaged whisky, is then placed in oak casks to mature. By law, all Scotch whisky must be aged for a minimum of three years in oak casks, though many single malts are matured for much longer. The whisky continues to develop and change as it spends time in the wood, and maturation periods of twenty years or
Single malt whisky not always clear what the term "single cask" refers to. At least some producers release vattings of multiple barrels that have been matured together for one final period in a larger single cask as "single cask" whisky. While cask-strength, or undiluted, whisky (sometimes having an alcohol content upwards of 60%) has recently become popular, the vast majority of whisky is diluted to its "bottling strength" - between 40% and 46% ABV - and bottled for sale. Whisky can be "chill filtered": chilled to precipitate out fatty acid esters and then filtered to remove them. Most whiskies are bottled this way,