There are two ways to define Blended Whisky.

An American Blended Whisky must contain a minimum of 20% straight whiskey, but the rest of the blend can be comprised of any category of whiskey and/or neutral grain spirit.

In Blended Whisky from Scotland, Ireland, or Japan, the product must be comprised of both single malt and single grain whiskies. Scotch and Irish Blended Whisky must be aged for a minimum of three years, and Irish Whisky alone can include pot still in its blend.