Alcohol proof. What is it? Is it various in various countries? just how did it acquire that name? You’ve involved the right ar for answers.

You are watching: Proof is the percentage of alcohol in a drink by volume, so 40 proof means 40% alcohol.


I. Shooting powder Test

II. Alcohol evidence Varies

III. Alcohol Equivalence

IV. Cullen-Harrison

V. Resources

I. Shooting powder Test

So what’s alcohol proof? In the early on 1700s, people measured the alcohol contents of distilled beverages by making use of gunpowsder. The is, they would “prove” the beverage acceptable.

To carry out so they poured some on gunpowder and also lit it. If it melted steadily through a blue flame, it to be 100 degrees “proof” and equaled 57.15 ethanol. If it did not burn, it to be “underproof.” and also if it melted too conveniently it was “overproof.”

II. Alcohol proof Varies

United Kingdom

In the united Kingdom, 100 alcohol proof equates to 57.1% ethanol by volume. The gunpowder test is the origin of this definition of proof.

United States

In the united States, alcohol evidence is twin the percentage of alcohol in a solution. That’s as soon as the systems is at 60 degrees Fahrenheit or 15.6 degrees Celsius. Thus, 150 proof would be 75% alcohol and also 100 proof would be 50% alcohol.


Pure alcohol (200 proof alcohol) rarely exists external a laboratory. That’s because if pure alcohol is open to the air, it will absorb moisture from the atmosphere. Hence it will self-dilute down to about 194 proof. 
FranceIn France, alcohol content is in levels Gay-Lussac (GL). A technician tests the systems with a hydrometer. Then the person expresses alcohol toughness as parts of alcohol every 100 components of the mixture. Thus, a soul with 40% alcohol by volume amounts to 40 degrees GL.


The worldwide Organization of legit Metrology recommends how to measure alcohol strength. A technician distills away every the alcohol, condenses it, and also weighs it. The human being then expresses the results as a percentage of alcohol by weight (ABW).

Alternatively, the technician steps the volume the alcohol distilled and also expresses it as a portion of alcohol by volume (ABV). The person performs the measurement in ~ 20 levels Celsius or 68 degrees Fahrenheit. Separating ABW through .079 counter it come ABV.

III. Alcohol Equivalence

The alcohol proof of typical drinks the beer, wine and spirits (liquor) differ. However each contain an tantamount amount of alcohol. The is, 0.6 ounce each.

This truth is an extremely important. Human being tend to fool themselves. They don’t recognize that conventional servings that beer, wine, and spirits have actually the very same amount of alcohol. In fact, they’re all the same to a breathalyzer.

IV. Cullen-Harrison

Congress happen the Cullen-Harrison “non-intoxicating beverage act” together the repeal of ban neared. The act raised “non-intoxicating liquors” from 0.5% come 4% ABV (3.2% ABW).

more Trivia!

Mississippi had state-wide barred of every alcoholic beverages for one-third that a century after the repeal of national Prohibition. Hundreds of prohibition or dried counties exist across the united States. They make up virtually 10% the its area. 
This legalized low alcohol proof beverages. However, states could specifically maintain their own prohibition. As a result, 20 states and also the ar of Columbia started permitting the revenue of low proof alcoholic beverages. Lock did for this reason on April 7, 1933, as soon as the law ended up being effective.

The 21st Amendment repealed the 18th revised (and nationwide Prohibition) ~ above December 5, 1933. That course, Repeal make the Cullen-Harrison act meaningless. However, the 21st Amendment gives states the ideal to define and also regulate alcohol addict beverages within your borders.

Today, 6 states continue to use the old Cullen-Harrison definition. The is, the 3.2% ABW or much less are “non-intoxicating.” They space Colorado, Kansas, Minnesota, Missouri, Oklahoma, and Utah.

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V. Resources: Alcohol Proof

Web Pages

Alcohol Equivalence

Alcohol Trivia


Inter Cent Alco Pol. Reduced Alcohol proof Beverages. Washington: The Center, ICAP Rep #19.