Straight bourbon whiskey is a type of American whiskey made primarily from corn, with at least 51% of its grain content being corn. It must be aged in new charred oak barrels for a minimum of two years. If it is aged for less than four years, the age must be stated on the label. To be labeled as "straight," the whiskey must also meet specific legal requirements, including being distilled to no more than 160 proof and entering the barrel at no more than 125 proof. This process gives straight bourbon its distinct flavor profile, characterized by sweetness and rich caramel notes.