Bourbon whiskey bottled at essentially the same alcoholic strength at which it left the barrel, with its bottling proof no more than two proof degrees below its proof when dumped. It must otherwise meet all federal requirements for bourbon: produced in the United States from a mash containing at least 51% corn, distilled at no more than 160 proof, entered into charred new oak containers at no more than 125 proof, and bottled at 80 proof or higher. Barrel-proof bourbons are typically robust and concentrated, with pronounced oak, spice, caramel, and grain character. Also called “cask-strength bourbon.”