Blackened Cask Strength American Whiskey is a collaboration between heavy metal megastars Metallica, the sound engineers at Meyer Sound, and legendary Master Distiller Dave Pickerell, this blended whiskey uses unique sound treatment during its aging process. Heres how its made: First, its not a bourbon or a rye, but a blend, of bourbon, rye, and other whiskeys all unspecified. The whiskey is pummeled by sound specifically, the music of Metallica causing it to seep deeper into the barrel, where it picks up additional wood flavor characteristics.