You’ve observed that the proof of an alcoholic beverage is twice the amount of alcohol in the bottle, but what exactly does proof of alcohol mean? “Proof” is one of those alcohol terms that you probably assume only the upper crust uses to describe the alcohol concentration in liquors.

**Table Of Contents**

−- What Is the Definition of Proof in Alcohol?
- How did the term “proof” come to be?
- The Meaning of “Proof”
- Why is proof used to measure alcohol?
- Why isn’t “Proof” used to measure beer and wine?
- How Is the Proof of Alcohol Measured Around the World?
- What Is the Distinction Between ABV and Proof?
- How is ABV calculated?
- Labeling of Proof
- The Weakest Proofs
- The highest Proofs
- What Constitutes “Normal” Alcohol Proof?
- What Does the Phrase “70 Proof” Mean?
- What Does the Term “80 Proof” Mean?
- Why is 80 proof the magic number?

If you’re like me, you believe placing evidence on a label is the most worthless thing in the world. Why do we need the amount of alcohol shown twice on the bottle?

While there may or may not be a legitimate explanation, the proof of an alcoholic beverage may reveal a lot about what’s within your bottle.

## What Is the Definition of Proof in Alcohol?

Alcohol proof is a proportion of alcohol used to assess the strength of spirits (aka hard alcohol or hard liquor). The proof is derived by doubling the proportion of alcohol by volume contained in each spirit.

For example, an 80-proof spirit has 40% alcohol by volume (ABV percentage). The higher the alcohol proof, the stronger the alcohol.

The term “evidence” dates back to the sixteenth century in England. It was used as a rough measure of alcohol level for rum and other beverages.

## How did the term “proof” come to be?

The term proof originated in the 18th century when sailors unloading their ships of goods and whiskey had only one means to determine the strength of the liquor they were carrying: they mixed a small amount of whiskey with a pinch of gunpowder. They dropped a lit match into the mixture.

If it exploded with an audible “proof!” the sailors knew it contained at least 50% alcohol.

The “gunpowder test” was a rudimentary method created to determine the amount of ethyl alcohol in various batches of rum.

Government personnel would dip gunpowder in the measured spirits and then attempt to ignite it. If it caught fire, the liquor had more than 57 percent alcohol. This is the bare minimum of flammability.

## The Meaning of “Proof”

In any case, the term “proof” derives from a test used to determine the quantity of alcohol in liquor. The wine was ignited by combining it with gunpowder.

If nothing happened, it was said that the bottle had been watered down. If an ignition or explosion occurred, the bottle was “proofed” to contain an appropriate quantity of alcohol.

Our proof system in the United States was developed about 1848 when alcohol containing 50% alcohol was considered as 100 percent for tax reasons.

As a result, the practice of doubling the alcohol concentration to calculate an alcohol’s proof arose. This was a wholly random benchmark chosen since liquor with a 50% alcohol level was thought to be quite usual for powerful liquors.

Taxes were calculated based on how much higher or lower the bottle’s proof was in comparison to 100 proof.

## Why is proof used to measure alcohol?

The practice of measuring alcohol strength by proof originates in the United Kingdom. England taxed spirits, mostly rum, based on the amount of alcohol in them as early as the 1500s. However, there were no easy means to calculate this number.

This early process resulted in the phrase “evidence.” On the other hand, the current standard is not founded in any manner on gunpowder. In the mid-nineteenth century, 50 percent ABV was considered a minimum for marking spirits as “100 proof.”

As a result, the contemporary proof method is just doubling the ABV of any given spirit.

## Why isn’t “Proof” used to measure beer and wine?

The origin of the term “proof” explains why beer and wine are not measured by it. The proof was produced for tax purposes when spirits were created in 16th century England. Only alcoholic beverages with high alcohol content are taxed. Because spirits had a high alcohol concentration, they were “proofed.”

On the other hand, beer and wine were not tested for evidence. Even the strongest beers and wines fell far short of the 57 percent ABV mark that marked the proof threshold. When the contemporary nomenclature was established, beer and wine were omitted from this hard alcohol measurement.

## How Is the Proof of Alcohol Measured Around the World?

Depending on the country, alcohol proof is now measured differently. Here are three methods for measuring it:

In the United States, alcohol proof is twice the ABV percentage. A liquor containing 60% alcohol is 120 proof in the United States.

In France, the Gay-Lussac scale was designed in 1824 by French scientist Joseph-Louis Gay-Lussac and utilized “degrees GL” as its unit of measurement. In France, alcohol proof is considered to be precisely equal to the ABV %. In France, a beverage containing 60% alcohol would be 60 degrees proof (or 60 degrees GL).

Internationally, the European scale devised by the International Organization of Legal Metrology is used by most countries, including the United Kingdom (OIML).

This straightforward approach, commonly known as the ABV standard, is virtually the same as the Gay-Lussac scale, except that no conversion to proof is required. So a liquor containing 60% alcohol would be labeled as 60% ABV.

In the United Kingdom, “proof” was approximately 1.821 times the ABV. As a result, proof numbers in the United Kingdom differed from those in the United States, resulting in many confused and inebriated travelers traveling overseas.

However, proof in the EU, UK, and Canada have all gone the way of ABV, leaving the US to stand alone with a weird and arbitrary measuring method (see feet, pounds, etc.).

## What Is the Distinction Between ABV and Proof?

Every alcoholic beverage label, whether wine, beer, spirit, cider, or hard seltzer, must state the amount of alcohol contained. The variety of ways it might be worded can be perplexing.

Alcohol-by-volume (abv) and proof are the two most used techniques for indicating a beverage’s alcoholic content. The proof of a spirit in the United States is double the abv.

This implies that a bottle of 90-proof bourbon has 45 percent alcohol by volume, whereas a bottle of 151-proof rum contains 75.5 percent alcohol by volume.

## How is ABV calculated?

Because ABV is the basis for calculating alcohol proof, it’s useful to understand how alcohol by volume is calculated. There are two techniques for measuring alcohol: measuring by volume and measuring by mass.

Mass determination is not temperature sensitive, but the more usual proportion (percent) of the total volume is.

Volume percent (v/v percent) measurements must be done at 20 °C (68 °F) according to the International Organization of Legal Metrology (OIML).

ABV can be measured in European Union countries using either mass or volume.

In the United States, the alcohol content is expressed as a percentage of total volume. Although most liquors also mention a proof, the proportion of alcohol by volume must be labeled.

For spirits with no solids and more than 100 ml in volume, the alcohol level may fluctuate within 0.15 percent of the ABV listed on the label.

Although the UK-proof system may still be seen and heard, Canada officially utilizes US labels indicating percent alcohol by volume. Familiar spirits at 40% ABV are referred to as 70° proof, whereas spirits at 57 percent ABV are referred to as 100 proof. Over-proof rum is a rum that has more than 57 percent ABV or above 100° UK proof.

## Labeling of Proof

If the logic behind our proof system wasn’t enough to make you doubt its legitimacy, consider this: alcohol isn’t even required to be labeled with its proof.

Some liquors are defined by their proof. However, this is usually followed by the percentage of alcohol concentration that the proof reflects. The alcohol level in percent alcohol must always be stated on the bottle of alcoholic beverages.

So why do we continue to publish the evidence on the bottle? Sentiment? To save a little piece of history? It appears to be a case of “we’ve always done it. Therefore we’ll always do it.”

On the other hand, knowing its origins provides you with a terrific narrative to tell at parties. Maybe it’ll motivate you to light up your booze responsibly, for science’s sake.

## The Weakest Proofs

As obvious as it may appear, many people refer to and characterize alcohol by its evidence. Any alcohol can be discussed in terms of proof. However, beer, wine, and other low-alcohol beverages aren’t commonly described by proof.

The phrase is usually reserved for liquors, which have far higher alcohol content variations than different varieties of beer.

Any bottles of flavored brandy, gin, vodka, rum, and whiskey can have the lowest proof and yet be considered liquor. They can all be diluted to 40 proof while meeting their legal meanings.

This is fantastic news for those of us who want to have a delicious taste drink without having a headache the next morning. In general, selecting a flavored liquor will result in a lower-proof bottle.

Malibu is 42 proof, flavored vodkas like Smirnoff and Burnett’s are normally about 70 proof, while Fireball is just 66 proof. These are far weaker than their unflavored, pure cousins, which must be no less than 80 proof.

## The highest Proofs

True liquors can have proof levels as low as 80 percent and as high as 192 proof. Spirytus vodka, a Polish vodka with a proof of 96 percent, wins the award for highest-proof alcohol. Everclear, which is 190 proof, is close behind. Both are (largely) legal in the United States and are considered harmful.

The greater the proof, the more calories you consume each shot. You’ll also experience more severe hangovers and become inebriated more quickly.

That final bit seems enjoyable, but the more you drink, the heavier your pour becomes, and nothing screams alcohol poisoning like a couple of shots of 95 percent pure alcohol.

Not to mention that alcohol above 101 percent is deemed explosive, and the common use of lighters at parties may be hazardous.

That is not to suggest that these high-proof liquors cannot be drunk responsibly. To get your fill of higher proof liquors, try Sunset Rum (169 proof), Bacardi 151 (151 proof, if you didn’t know), or Booker’s Bourbon (130 proof).

Fortunately, alcohol with high proof considers this trait a badge of honor. Thus they are prominently labeled with their alcohol level.

The fact that everyone still counts proof on bottles may not make much sense, but knowing that the phrase originated from burning booze to test if it caught fire makes it acceptable, in my opinion.

For the time being, it appears that we will continue to define liquors by their proof. Thus, it’s useful to know that grabbing a bottle of Bacardi 151 will have a very different effect than Bacardi Razz (64 proof, if you’re curious).

## What Constitutes “Normal” Alcohol Proof?

“Normal” alcohol proof is less than the quantity that inspired the phrase in the first place. Today, anything between 40 and 100 proof is considered “normal.” Above that, spirits begin to approach flammability. High-strength alcohols are hazardous to one’s health and property in the event of a fire.

As previously stated, each form of spirit has a “normal” or usual evidence. Rum, tequila, gin, vodka, and whiskey are normally 80 proof. However, this might vary depending on the batch.

While some liquors (mostly rums and vodkas) may appear strange owing to their extremely high proofs, they are nevertheless normal in the sense that they are lawful to make.

## What Does the Phrase “70 Proof” Mean?

The term “70 proof” implies “35 percent ABV.” It is most commonly used for flavored spirits and higher-proof liqueurs.

Because proof only measures hard alcohol, 70 proof is on the lower end of the scale. This is because spirits are designed to have a greater ABV than beer or wine, with an ABV of less than 15%.

## What Does the Term “80 Proof” Mean?

ABV of 40% is comparable to 80 proof. It is the most often used proof measurement for alcoholic beverages. The majority of rums, tequilas, gins, whiskeys, vodkas, and cognacs are 80% or higher.

## Why is 80 proof the magic number?

Spirits include a significant amount of alcohol. The alcohol provides the drink shape and texture, as well as helps to enhance the flavor. The key to creating a flawless spirit is to strike the ideal balance between alcohol concentration and taste.

This equilibrium is most commonly observed at roughly 40% alcohol concentration. Because this recipe has stood the test of time, spirits like vodka, tequila, and white rum are virtually always bottled at 80 proof.

However, some spirits, such as whiskey, can be bottled at 120 or higher. These liquors, however, are not intended to be consumed directly. They are commonly used as ingredients in cocktails.

Another reason why companies bottle spirits with the bare minimum of alcohol is to save money. The greater a bottle’s proof, the more it will be taxed.

Though some specialist spirit brands will experiment with liquors that exceed this 40% level, it just isn’t worth it for mass-producing, conglomerate firms. There isn’t enough demand, and it’s not worth paying more taxes.

Have you ever had a spirit that was devoid of acidity? Or perhaps a martini that lacked enough oomph? The alcohol in a drink does more than get you intoxicated; it influences the whole drink.

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