What does 'barrel proof' mean?

Barrel proof refers to a spirit that is bottled at its original strength, meaning it has not been diluted with water after the distillation process. Spirits that are labeled as barrel proof retain the alcohol concentration at which they were aged in the barrel, showcasing the full intensity and character of the spirit. This term is often associated with bourbons and rums, where the alcohol by volume (ABV) can be significantly higher than standard bottlings, providing a robust flavor profile that many enthusiasts appreciate.

The other options do not accurately reflect the meaning of barrel proof. A spirit diluted with water before bottling would be lower in ABV and not represent the original strength. Aging in used barrels is unrelated to the proof of the spirit, as it focuses on the aging process rather than the bottling strength. Flavored spirits may also involve the addition of ingredients post-distillation, which does not pertain to being barrel proof. Thus, the definition of barrel proof specifically highlights the unaltered strength of the spirit right from the barrel to the bottle.