Question: 80 proof is how much alcohol?
Answer: What is being proven, exactly? Vodka contains 40 percent alcohol, or 80 proof. One of the first things taught in Drinking Alcohol 101 is the definition of the term “proof”: In the U.S., it's the percentage of alcohol, times two. For example, if a bottle of vodka is 40 percent alcohol, it's 80 proof.