eli5 – How does the % in alcohol work?

Question

Is 13% of a bottle of wine 13% full of alcool or is it another formula?

In: 4

Answer 1

[Proof](https://en.wikipedia.org/wiki/Alcohol_proof) is double the ABV and an old and arcane measurement. It’s actually much more complicated until we could measure specific gravity. Alcohol was “above proof” if it could be ignited with a match.