波本威士忌
After maturing, bourbon is withdrawn from the barrel and is typically filtered and diluted with water. It is then bottled at no less than 80 US proof (40% abv). Although most bourbon whiskey is sold at 80 US proof, other common proofs are 86, 90, and 100. All "bottled in bond" bourbon is 100 proof. Some higher-proof bottlings are marketed as "barrel proof", meaning they have not been diluted or have been only lightly diluted after removal from the barrels. Bourbon whiskey may be sold at less than 80 proof but must be labeled as "diluted bourbon".