Why do bourbons that have been aged for less time have a higher proof than those aged for longer?

Question

I understand this isn’t always the case, but I see bottles of 10 year 107 proof for example and a 20 year 95 proof right next to it. What makes this difference?

In: Chemistry

Answer 1

Because alcohol evaporates; the more time in a porous barrel, the more alcohol evaporated out