What does "drinking proof" refer to in bourbon?

"Drinking proof" refers specifically to the proof at which bourbon is bottled for consumption. Proof is a measure of the alcohol content in a spirit, and it is calculated as twice the percentage of alcohol by volume (ABV). For example, if a bourbon is bottled at 50% ABV, it will have a drinking proof of 100. This is important for consumers as it provides an indication of the strength and intensity of the flavor profile they can expect when drinking the bourbon. The terms used in the other answer choices do not accurately convey this concept. For instance, while the final water added to a bourbon can influence its overall flavor, it is not what "drinking proof" explicitly refers to. Furthermore, the proof during distillation and the measure of quality do not align with the notion of drinking proof, which is concerned solely with the final bottling proof for consumer use.