Metallica teamed up with master distiller and blender Rob Dietrich to create BLACKENED American Whiskey. Each batch of Blackened has a unique playlist that was used to sonically-enhance the whiskey during finishing. As the well-aged whiskey rests in the finishing barrels, the music is played to the barrel causing the whiskey inside to move and interact with the wood. The movement of the whiskey and the amount of interaction depends on the song being played, so the variation of the music creates a slight nuance from one batch to the next. Throughout this process, Dave tests the whiskey to determine the optimal color and flavor profile for each batch.