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
Barrel to produce a whisky branded as "Jameson Caskmates". Cask ale is aged in the barrel (usually steel) for a short time before serving. Extensive barrel aging is required of many sour beers. Vernors ginger ale is marketed as having a "barrel-aged" flavor, and the syrup used to produce the beverage was originally aged in oak barrels when first manufactured in the 19th century. Whether the syrup continues to be aged in oak is unclear. Some of the liquid stored in a barrel is absorbed into the wood. The barrels can be more or less porous, depending on the wood; more