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
Blended malt whisky single malt whisky produced from the same distillery is still considered a single malt whisky. The "malt" part of the term refers to the use of a malted grain to make the whisky. In Scotch whisky, this grain is required to be barley. Outside Scotland, whisky is produced from other malted grains, such as malted rye, and the term "rye malt whisky" is specifically recognized along with (barley-based) "malt whisky" in the code of federal regulations for whisky in the United States. Moreover, in much of the world, whisky is often made using grain that is not malted (for example,