Wine Gallons and Proof Gallons: Definitions, Uses, and Differences
Both wine gallons and proof gallons are used for a variety of purposes and are closely connected to one another. Wine gallons can be used to help measure proof gallons and vice versa.
Quick Summary
| One wine gallon | One volumetric gallon or 128 fluid ounces (fl. oz.) of liquid |
| One proof gallon | One volumetric gallon containing 50% ethyl alcohol (ethanol) |
Wine Gallon
A wine gallon is a measurement of any liquid's total volume. One wine gallon is equal to 128 fl. oz. or 3.78 liters (L). Wine gallons are not used to exclusively measure wine. The term originated in England in the 14th century and was used to measure wine, cooking oils, honey, and more.
Proof Gallon
A proof gallon is a measurement of only the ethanol contained in a given volume of liquid. One proof gallon is equal to one wine gallon of liquid containing only 50% ethanol. The other 50% is typically water but can technically be any liquid so long as it is not ethanol.
To better understand a proof gallon and how it is used, look at how the proof of a container alcohol is calculated. ABV refers to alcohol by volume, which is a percentage that, essentially, reflects how much a container of alcohol has been diluted. For example, 100% ABV means the alcohol has not been diluted at all -- it's 100% alcohol or ethanol; 95% ABV means the alcohol has been diluted with 5% water (or other diluting liquid that is not alcohol) -- the container holds 95% alcohol and 5% water; and 50% ABV is a container of 50% water (diluting liquid) and 50% alcohol. To identify the proof of a liquid, multiply the ABV by two.
100 (100% ABV) x 2 = 200 proof
95 (95% ABV) x 2 = 190 proof
50 (50% ABV) x 2 = 100 proof
Thinking back to the proof gallon, it makes sense that a container that is 100 proof is equal to one proof gallon (50% water, 50% alcohol). Similarly, a 200-proof container of alcohol is equal to two proof gallons, and a 190-proof container of alcohol is 1.9 proof gallons.
One proof gallon is equal to...
One wine gallon at 50% ABV
Two wine gallons at 25% ABV
One half wine gallon at 100% ABV
Why Use Proof Gallons
Because proof gallons measure the amount of ethanol present in a contained volume of liquid, federal excise taxes are calculated based on proof gallons.
Quick Reference for Common Volumes of Liquid as Proof Gallons
| 750 milliliters (ml) of 80 proof (40% ABV) vodka | 0.158 proof gallons of ethanol |
| 12 ounces (oz) of 10 proof (5% ABV) lite beer | 0.0009375 proof gallons of ethanol |
| 55 gallons (gal) of 190 proof (95% ABV) Culinary Solvent | 104.5 proof gallons of ethanol |
| Five gal of 200 proof (100% ABV) Culinary Solvent | 10 proof gallons of ethanol |
