According to United States federal legal standards (specifically the Alcohol and Tobacco Tax and Trade Bureau regulations), authentic bourbon must adhere to specific production criteria: (1) It must be made within the United States; (2) It must be produced from a grain mixture containing at least 51% corn; (3) It must be distilled to no more than 160 proof (80% alcohol by volume); (4) It must be aged in new, charred oak containers; (5) It must be entered into the barrel at no more than 125 proof (62.5% alcohol by volume); and (6) It must be bottled at no less than 80 proof (40% alcohol by volume). While often casually referred to as a seven-part rule set by traditionalists, the legal framework centers strictly on these foundational mashbill, distillation, and barrel-aging parameters.