Picking out the perfect barrels for Jack Daniel's Single Barrel - Barrel Proof Whiskey is a highly selective process. Only one out of every 100 barrels we produce is deemed worthy of the distinction. These highly coveted barrels age in the highest reaches of our barrelhouses; where extreme temperature variations increase the interplay between wood and whiskey. Jack Daniel’s Single Barrel Barrel Proof is whiskey as nature intended it—bottled straight from the barrel at its full proof. Intense, smooth, and remarkably varied, Barrel Proof is bottled at anywhere from 125 to 140-proof, taking Jack’s trademark vanilla and toasted oak flavors to bold new levels.