100 proof rum contains what percentage of alcohol
Alcohol proof The proof system in the United States was established around 1848 and was based on percent alcohol rather than specific gravity. 50% alcohol was defined as 100 proof.[1]
Standard drink For example, 0.35 litre glass of beer with ABV of 5.5% has 15.2 grams of pure alcohol. Pure alcohol has density of 789.24 g/l (at 20 °C).