If a liquor bottle reads 100 proof, what is its alcohol content expressed as a percentage?

When a liquor bottle is labeled as 100 proof, it indicates that the alcohol content is 50% by volume. The proof system used in the United States defines proof as twice the percentage of alcohol by volume (ABV). Therefore, to determine the alcohol content, one simply divides the proof by two. Since 100 proof divided by two equals 50%, this shows that the liquor contains a significant amount of alcohol, making it a strong spirit. This understanding of proof and its relationship to alcohol content is essential for bartenders, as it informs decisions about mixing drinks, serving sizes, and recognizing the strength of various liquors.