Bourbon is an American Spirit that by definition is a whisky produced in the US at not exceeding 160 proof from a fermented mash of not less than 51% corn and stored at not more than 125 proof in charred new oak containers and bottled at no less than 80 proof. While there are no minimum specified aging requirements for Bourbon, there are subcategories with age registrations. Straight Bourbon must be aged a minimum of two years. Any Bourbon aged less than four years must include an age statement on the label. Bourbon subcategories include: Straight Bourbon, Blended Bourbon, Bottled In Bond and Wheated Bourbon.