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
American whiskey it is aged, it must be aged in used or uncharred oak barrels "at not more than 62.5% alcohol by volume (125 proof)". In practice, if corn whiskey is aged, it is usually aged in used bourbon barrels. Straight whiskey is whiskey that was distilled to not more than 80% alcohol by volume (160 proof) that has been aged for at least two years at a starting alcohol concentration of not more than 62.5%. It has not been blended with any other spirits, colorings, or additives. A straight whiskey that also meets one of the other above definitions is referred