Bundaberg Over Proof Rum 700ml

Bundaberg OP Rum has been around as for as long as it's Underproof brother.  It is based on the same spirit, and blended to the higher strength by adding less pure water in the marrying tanks than UP Rum.  

What is the meaning of "Overproof" or OP?  The term originated in the UK in the 18th century when British sailors payment included rations of rum.  The term means the dilution point of a spirit that would sustain the ignition of gunpowder.  The sailors wanted to “prove” that their spirit had not been watered down.  Gunpowder was doused with the rum and if it ignited, it was over proof.  If it did not ignite to much water had been added to the rum and it was considered “under proof”.  57.15% Alc/Vol was found to be the lowest point at which the gunpowder ignited and was defined as “100 Degrees Proof”.

Now days, BDC use hydrometer to measure the alcohol content.  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.