Malt whisky whisky regulations require malt whisky to be made in pot stills using water and malted barley without the addition of any other cereals, and the whisky must be aged for at least three years in oak casks. The use of new barrels is not required. Caramel coloring can be added, but no other additives are allowed. Irish whiskey regulations are almost identical to Scotch regulations. Malt whiskey must be distilled in a pot still from a mash of 100% malted barley, which may be peated or unpeated in character, although unpeated malt is typically used. All Irish whiskeys must be
Scotch whisky also encounter the term "single cask", signifying the bottling comes entirely from one cask. The term "blended malt" signifies that single malt whisky from different distilleries are blended in the bottle. The Cardhu distillery also began using the term "pure malt" for the same purpose, causing a controversy in the process over clarity in labelling – the Glenfiddich distillery was using the term to describe some single malt bottlings. As a result, the Scotch Whisky Association declared that a mixture of single malt whiskies must be labelled a "blended malt". The use of the former terms "vatted malt" and "pure