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
Cask strength on storage conditions. Scotch whisky is typically aged in used barrels, and due to the relatively cool climate in Scotland, the proof level typically stays the same or goes down during maturation. In contrast, American bourbon whisky is produced using new barrels, and storage conditions in Kentucky and Tennessee where nearly all of it is produced allow the proof levels to rise during aging. The vast majority of whisky bottled has been watered down to about 40–46% ABV, although some whiskies marketed for whisky enthusiasts are bottled at proof levels all the way up to cask strength. In the United