You probably know that the word proof (as in booze) comes from the tax inspectors in the good old days that used to put a pile of gunpowder on the bar, buy a nip of spirits and pour it over, then light it. If the gunpwder burned at the end it was proof that the spirits had not been watered down. I am told that some of the bars in old pubs in England still have the burn marks on them. Proof is about double the percentage w/v. Ordinary whiskey is 43% and vodka about 38% I think so it is not super strong. Should still burn though. What a waste.