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What is Proof in Whiskey? A Complete Guide (2022)

Last Updated on November 9, 2022 by Lydia Martin

Whiskeys were not just alcoholic beverages but were prescribed as medicine before Volstead Act 1920. They distributed over 1.5 million of 90-100 proof whiskeys to registered druggists and doctors.

The question is, how did they determine the proof? And what exactly is whiskey proofing?

Let’s learn about the whiskey-proof meaning, its purpose, and how it evolved from its inception.

What Is Alcohol Proof In Whiskey?

Whiskey Brands on desk

Alcohol proof in whiskey or any other alcoholic beverages is the measurement of alcohol inside the bottle. 

It started in England, where the government based the amount of tax placed on each barrel on the product’s potency. They use gunpowder to test the potency by lighting it up. If it ignites, then that proves that alcohol is high. 

Over the years, proofing liquors continued and applied in more scientific ways. Also, different countries have their measurements utilized.

Why Is Alcohol Measured In Proof? 

Alcohol is measured in proof to determine its potency. In the earlier years, when the metric system was not yet discovered, gunpowder was used to determine if the liquor would ignite.

It became the “literal” proof that it has absolute alcohol, not diluted in water. 

This method was improved using a more accurate formula and scientific-based computations.

However, your location is vital to your percentage as it differs in the US, UK, and other parts of the world.

Whiskey’s Average Alcohol Proof 

Rebel 100 on table with glass

After the Prohibition in 1933, whiskey’s alcohol proof bordered at 90-100 proof, while a few went as low as 84-proof. However, in the early 90s, when the excise tax increased and scrutinized alcohol’s impact, it slightly changed. 

Whiskey and all other spirit manufacturers lowered the strength to a 40% ABV limit or 80-proof minimum.

The Alcohol and Tobacco Tax and Trade Bureau permits proof on the labels. However, the ABV content is required to be written. Learn how to make whiskey taste better here

When Was It First Used? 

According to history, this was first used in the 18th century by the British Royal Navy. The soldiers tested the potency of the liquors with gunpowder pellets.

 Although this was unreliable, the government utilized this approach to levy taxes. If the pellets ignite after soaking in the liquid, they are deemed over-proof and are taxed higher. Those that did not ignite were labeled under-proof.

Read: Can You Age Fine Whiskey Overnight?

Why Alcohol “Proof” Has Different Meanings 

Why Alcohol “Proof” Has Different Meanings 

Alcohol proof has different meanings because the standard of measuring alcohol worldwide differs. The conversion from proof to ABV in the US is very simple, just multiple ABV contents by two. 

It may be a confusing value in the UK as their conversion showed 57.06% ABV is the threshold. Meanwhile, France uses degrees Gay-Lussac scale [2] measurement instead of proof which is equal to a 1:1 ratio.

It means that if the whiskey has 100 proof, it is also 100GL. 

Therefore, if the whiskey is 100 proof in the US, it will be 50 proof in France and 87.6 proof using the British scale

Do Brands Still Use This Unit of Measurement?

Yes, brands still use this unit of measurement, technically. There may be changes in the metric measurements used in each country, but equivalent alcohol contents are computed accordingly.

These are then placed on the labels, although the law requires just the alcohol by volume. Proof information is still commonly displayed.

FAQs

Is 100 the standard alcohol proof for whiskey?

Yes, 100 is the standard alcohol proof for whiskey. It was the definitive proof stated in the Bottled-in-Bond Act of 1897 but only applies to a single distillery, distiller, or season product.

It exempts cask and barrel strength whiskeys

Do other liquors aside from whiskey use alcohol proof?

Yes, other liquors aside from whiskey use alcohol. Wines and spirits like vodka, rum, brandy, tequila, and gin also use proof to identify their alcohol strength. But what’s the highest proof whiskey?

Key Takeaways 

Whiskey proof is simply the alcohol by volume multiplied twice.

The potency of your drink relies on its proof. Your location also matters since not all countries use the same measurement.

The bottom line is that being aware of how much alcohol is in your drink will help you with your alcohol consumption.

References: 

  1. https://www.brown.edu/Departments/Joukowsky_Institute/courses/13things/7687.html
  2. https://www.thoughtco.com/guy-lussacs-gas-law-example-607555

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