Question: what is the difference between overproof and underproof rum?
Answer: The term "proof" now refers to an alcohol content of 50% by volume, or 100 proof. Underproof means the rum is less that 50% Alc/Vol and Overproof means the rum is over 50% Alc/Vol. Bundaberg Rum OP is blended to 57.7% Alc/Vol.