Tennessee whiskey, of which Jack Daniel’s is the most famous, is a bourbon whiskey made from corn, rye, and barley, and taken one step further by filtering it through a ten-foot-thick layer of hard sugar-maple charcoal. This filtering process creates a whiskey with a smooth, rich, and spicy flavor and a dark amber color. Tennessee whiskey is made with a “sour mash” process—much like a sourdough starter—where some amount of the fermented mash from a previous batch of whiskey is used in a subsequent batch. This method controls the quality and flavor of the whiskey.