Why Is Alcohol Measured by Proof?

What does “proof” actually mean in terms of alcohol content?

How to Use a Proof & Tralle (Liquor) Hydrometer

Guide to ethanol purity measurement

Alcohol Proof: Definition, Measurement, & Is It Safe?

What Does “Alcohol Proof” Really Mean? – Uptown Spirits

Alcohol by volume - Wikipedia

Why does 'proof' have multiple meanings?

What Does the Proof on Alcohol Mean? Examples, Low vs. High

Formula for Figuring Cocktail Proof

how can you estimate the proof of a liquor