If you've ever wondered about booze bottles bearing those curious cask- or barrel- strength labels, then mystery revealed: It turns out that the liquor industry has quietly gone "extreme" in recent years. Special editions of whiskey, vodka, gin and other potent potables are now available in levels of 51 to 70 ABV (or 102 to 140 proof) – and a few far higher – compared with more typical 40 ABV/80 proof of garden variety distilled spirits. These high-strength brews not only pack an alcohol wallop, but many are extremely flavorful, and thus stand out better when used with mixed drinks than their more diluted siblings (yes, it's true, most spirits are cut with water). Since many are twice or more as strong as your typical tipple, they'll ring your bell though if you don't treat them with the proper respect. Pour poorly at your peril.