How much attention do you give to the proof or alcohol by volume (ABV) label on the alcohol you drink? This important number gives you valuable information about the amount of alcohol in your liquor. This helps you craft better drinks and drink responsibly. However, did you know that proof and ABV give you similar but not identical information? Similar to the metric and imperial system, proof and ABV are the result of different methods of measurement for alcoholic content testing getting developed. Understanding both will help you better understand the alcohol you’re enjoying. 

History of Alcohol Classification 

During the 16th century, England’s government decided to commence taxation of liquids with an alcohol content over a certain level. These original laws taxed alcohol that were above a predetermined level. However, this presented a new problem. A reliable testing system needed to be developed. At this time, chemical content testing was not established or reliable. This left people with the basics; will it catch fire? This became the “burn-or-no-burn” test.  

To perform this test, the alcohol containing liquid would get tested to see if it would catch fire. If it ignited, it would be “above proof” and subject to taxation. If the liquid didn’t catch fire, it would be “below proof” and not subject to taxation. Liquids that could sustain the combustion received a rating of “100 proof”. 

Unfortunately, this test is far from being exact. The temperature of the liquid heavily influences the flash point of alcohol. Alcoholic liquids that are closer to room temperature release more alcohol vapors. When this happens, the flammability increases. This led to parameters being put onto proof testing. Alcohol proof measurements should occur between 20% at 97 Fahrenheit and 96% at 55 Fahrenheit.

Gunpowder Test Method 

An early method for testing the flash point of alcohol was the gunpowder method. Instead of simply exposing the alcohol to flame, gunpowder is used. A gunpowder pellet gets soaked in alcohol. If the pellet can still ignite, then the liquid is above proof. The advantage of this test is that it is less vulnerable to changes in temperature. Unfortunately, the test is hard to reproduce, making it difficult to get consistent test results. The test used the potassium nitrate in the gunpowder to test the liquid’s combustibility. This presents a problem because multiple variables can skew the test results. For example, the grain size of the gunpowder or how long you allow it to soak will change how it behaves. 

Alcohol by Weight (ABW)

By the 17th century, it was established that the “Will it burn?” and gunpowder tests were inaccurate and unreliable. This led people to look for a more accurate measurement of alcohol content. This is when the alcohol by weight (ABW) measurement system was introduced in England. This testing method used gravity to define proof. The test compared the gravity of pure water at a temperature of 75 degrees Fahrenheit. A 100 proof alcohol would be 12/23 the gravity of the water. In other words, 100 proof is 50% ABW. It wasn’t until around the 18th century that the ABV measurement method we use today was developed. 

What Is Alcohol Proof? 

When stating alcohol proof, it uses the number 100. Anything above this number, the liquid has enough alcohol to burn. Anything below that number doesn’t have enough to be combustible. 

When in the United States, proof is twice the ABV measurement. So a liquor with 50% alcohol would be 100 proof. If the liquor were 40% alcohol, it would be 80% proof. France has a different proof measurement system. It states that proof and ABV are equal. 

What’s the Difference Between ABV and Proof?

While the system of proof and ABW were developed in England, similar alcohol measurements were needed in the United States and other countries. In the 1800s, the simplest solution was to define proof as double the alcohol percentage. So 100 proof became known as 50% ABV. This was a good baseline because 100 proof is the measurement level when alcohol readily ignites. 

In modern times, Europe and the rest of the world have largely abandoned the proof measurement system. Its lack of accuracy and consistency makes it too convoluted and unreliable for use as a worldwide rating system. 

ABV is the measurement system required by law. The European Union and US liquor laws require ABV to be stated on the bottle. In the US, proof is also printed on alcohol bottles, but mainly as a matter of tradition.

What Is Alcohol By Volume (ABV)? 

Measuring alcohol by volume (ABV) is a measurement in the metric system. It measures the volume of the liquid and then measures the volume of the alcohol in that liquid. The result is the percentage of alcohol in the liquid. Generally, the percentage of alcohol in a beverage will depend on the beverage type. 

• Beer: 3.5%- 7%
• Hard cider: 4.5%- 7%
• Wine- about 12%:
• Liquor: 40%- 50%

These measurements are averages that most beverages in the category fall into. However, there are always outliers that could be significantly higher or lower. This is especially the case with beer and wine, where artisans create unique offerings. Some craft beers could easily be 10-15%. There is even one beer that boasts a staggering 67.5% ABV. 

What Is A High ABV?

A high ABV is relative to the type of alcohol or drink you are talking about. For example, you look at a beer with a 7% ABV, and it is a strong beer. However, a glass of wine next to it with a 7% would be a weak wine. Then liquor could be anywhere on the scale. When comparing gin and vodka, gin has relatively low ABV volumes, around 30-50%. While vodka could be as high as 95% ABV. 

How to Calculate ABV

A specific formula is used to calculate a beverage’s ABV. You won’t have to worry about learning the formula, as alcohol sold today comes clearly labeled with its ABV percentage. However, it comes in handy to help you better understand what you are drinking or if you decide to make your own alcohol. To calculate your own ABV, subtract the final gravity from the original gravity. Then, multiply the result by 131.35. 

The original gravity is the hydrometer reading before the yeast is taken out. The final gravity is the hydrometer reading after fermentation finishes. The 131.25 number is the conversion factor between water and alcohol. The formula would look like this. 

(Final gravity – Original gravity) X 131.25

This isn’t an exact measurement. The relationship between original and final gravity is not linear. So, unfortunately, the measurement gets less precise as the alcohol content increases. 

Why are Beer and Wine not Measured by “Proof?”

Proof is a term that typically gets used for liquor but not beer or wine. This is partly because of the 100 score threshold. A 100 proof liquor would be 50% ABV. This measurement works well for liquor because it is typically around this ABV percentage or higher. Beer and wine are significantly lower. For example, you have a can of beer that is 5% ABV. It would have a proof of 10. Or a glass of wine with a 12% ABV measurement would have a proof of 24. These measurements are far below the 100 proof flash point that would allow them to ignite. 

In addition, a proof measurement is not an official or exact measurement. This means it is not a reliable method for conveying the amount of alcohol in a liquid. ABV is a more accurate test, thusly, a better measurement method for beer and wine where the amount of alcohol is so low. However, despite this, you may still hear people use the term proof when speaking about beer and wine. 

Where to Find ABV 

Most countries require alcohol makers to clearly print the ABV on the bottle’s label. It’s typically located on the bottom of the label. However, this isn’t always the case. Instead, you will see a number percentage or a number followed by “vol.” Both ways communicate the same thing, the percentage of alcohol in the liquid.  

The ABV of Popular Cocktails 

It is simple to read a liquor bottle and know its ABV measurement. However, things can get complicated when you start using liquor to make cocktails. The ABV could rise or fall depending on the other ingredients you add to the drink. Shaking with ice, adding mixers, or combining multiple liquors all change the ABV percentage of the drink. 

Carrying around a test kit isn’t practical. However, you should still keep an eye on the ABV percentage of the cocktails you are drinking. This will help you choose drinks that suit your tastes and drink responsibly. The solution is to do a rough estimate of your chosen cocktail’s ABV percentage. This will help you understand why two vodka martinis hit you harder than two negroni cocktails. Some drinks look enticing but pack a serious punch when it comes to alcohol potency. 

Factors that Impact Drink Strength 

How the cocktail gets made directly impacts the drink’s strength. The harder and longer the bartender shakes the drink, the more the ice melts. As a result, the drink gets watered down more, and the ABV reduces. Some bartenders have a heavy pour, while others are lighter. The heavier the pour, the more alcohol added, and the higher the ABV. Finally, drinks that require a top-off can vary significantly in ABV. This addition could range in volume from 4-6 ounces. For example, you could use a 7 or 10 ounce highball glass. The larger glass would require more soda water or ginger ale to top off a drink, thereby reducing the alcohol percentage of the drink. 

Cocktails High in ABV 

Generally, sipping cocktails and those with minimal ingredients are stronger than more complicated cocktails. The taller the glass, the more mixer ingredients get added, reducing the potency of the cocktail. Drinks that are shaken and served “up” tend to have the highest ABV percentage. This is because they have minimal mixers, and the ice is only used for shaking, not left in the glass. Finally, frozen concoctions are typically the weakest. However, this can be misleading. Many people overpour because they find frozen drinks weak. This can lead to a deceptively potent cocktail. 

Calculate a Cocktail’s ABV 

While the formula isn’t exact, you can use it to estimate the alcohol content of your cocktail. While it can seem confusing, it’s relatively simple once you us it. Look at this vodka martini recipe as an example. 

Vodka Martini Cocktail

2.5 oz vodka- 40% ABV

.5 oz dry vermouth- 15% ABV

.5 oz melted ice- standard dilution allowance

(Alcohol Content x Liquor Volume / Total Drink Volume) x 100 = % ABV

To calculate a vodka martini’s ABV, it would look like this: 

(.40 x 2.5) + (.15 x .5) = 1.075

(vodka’s alcohol content x liquor volume)+(vermouth’s alcohol content x liquor volume)

2.5 + .5 + .5 = 3.5 oz

(total drink volume)

1.075 / 3.5 = .30 x 100 = 30% ABV 

To interpret this, a standard vodka martini cocktail is 30% ABV. This makes it a strong drink. However, not as strong as drinking vodka straight. 

Now that you better understand the calculations and various dynamics of proof and ABV, you can venture out to sample and find new favorite spirits! Let Distillery Nearby be your guide!