Some like to measure the alcohol content of spirits by sticking their tongues into the liquid. No matter how attractive this idea might be, that’s not how professionals do it. When Uncle Flaviar took a stroll through the Cognac region, he got to experience the traditional method of measuring alcohol on some fine Cognacs.
Depending on where you live, there are two main systems for measuring the alcohol content of beverages. In the US, the alcohol content is measured in alcohol proof which is twice the percentage of alcohol by volume (ABV), used in Europe. Therefore, 150-proof rum has 75% ABV. Simple math, right? Right… until you start hanging out with Brits, whose proof system equals roughly 1.75 times of the alcohol by volume.
A Look Back in the History of Measuring Alcohol
Many different ways of measuring alcohol content evolved throughout history and gunpowder used to play an important role in that. See, in 16th century England, gunpowder was used for measuring the alcohol content of whiskies and other spirits.
Back in the day, spirits were taxed at different rates, depending on how much alcohol they had. A pellet of gunpowder was soaked in the liquid and could the pellet still be ignited afterward, the spirit would be rated as above proof and thus taxed at a higher rate.
Gunpowder would not burn in rum (spirit of choice back then) with less than 57.17% of alcohol by volume.
Rum with this percentage of alcohol was defined as 100 degrees proof—this is not to be confused with what 100 degrees proof means today.
The gunpowder test was officially replaced by a specific gravity test in 1816.
Traditional Equipment for Measuring Alcohol Content
Nowadays, some experts still like to use fairly traditional manual methods of measuring alcohol content, which is usually done with two similar-looking but very different glass contraptions: alcoholmeter and hydrometer.
While traveling through the Cognac region, our good friend Thibault Mauxion from Louis Royer was kind enough to demonstrate the measuring of alcohol content with the aforementioned traditional method.
The amount of alcohol in a pure base spirit (distilled spirit) is measured with the alcoholmeter. As soon as any sugar or other soluble substances are added to the spirit, the readings will be off. This is where its cousin, the hydrometer, comes into play.
First, the liquid is poured into a tall container, often a graduated cylinder, and then the alcoholmeter/hydrometer is gently lowered into the liquid until it floats freely.
Alcoholmeter is used to determine the volume of alcohol or proof. It is calibrated to the density of pure ethanol and is only to be used on pure, distilled Spirits.
Hydrometer, on the other hand, is calibrated to the density of water and is used during the pre-fermentation and post-fermentation phases. Hydrometers are used to determine the potential alcohol content.
Tips, Tricks, and Things to Look Out For in the Process
Alcohol readings also vary depending on the temperature of the spirit. The temperature that the instrument is calibrated to is usually listed on its side (20°C in most cases). Should the spirit still be warm when measuring its content, it will be “lighter” than at standard temperature, thus the meter will sink lower, making you think that it has more alcohol than it actually does.
Adding more sugar will also make the liquid thicker, thus the meter will be harder to sink. When fermentation occurs, the sugar is converted into alcohol, the liquid becomes thinner, and the meter sinks deeper.
If using a hydrometer, a reading is taken before and after fermentation and the approximate alcohol content is determined by subtracting the post-fermentation reading from the pre-fermentation reading.
Modern Alcohol-Measuring Methods
Today, many distilleries threw away their analog devices and replaced them with state-of-the-art digital alcohol meters, which are quicker and easier to use.
Operation of devices is easy, results are displayed in seconds and there’s no need to temperature-correct them. While they might be handy, we’re still asking ourselves where’s the fun in that?
Want to do a little 'alcohol testing' yourself? Grab a bottle from Flaviar's ever-expanding list of curated expressions you need to try or explore new flavor horizons with our award-winning Tasting Boxes™ including rare and high-end brands.
FAQs
Simply drop a distilling hydrometer in high proof alcohol and read the number on the side. It tells you proof / ABV directly without any calculation. Though there are a couple of caveats. First, just like a brewing hydrometer, a distilling hydrometer is "temperature sensitive" so you may need to correct for temp.
How do you calculate ABV and proof? ›
This terminology began in the the UK however in the US, currently the term Proof is determined by multiplying the alcohol % by volume (ABV) X 2. Thus an alcohol product labeled as 80 Proof is 40% alcohol by volume. An Alcohol product that is 50% ABV would be labeled at 100 Proof.
How do you measure alcohol percentage ABV? ›
To measure ABV, you make two measurements with the hydrometer, one before fermentation and one afterward. With these measurements, you are basically finding out how much sugar in the beverage changed into alcohol during fermentation.
How to test ABV at home? ›
What to Do: Measuring and Calculating Alcohol Using a Hydrometer
- Measure out about a cup of wort (or finished beer).
- Fill the hydrometer tube up to about 2 inches from the top.
- Insert the hydrometer. ...
- Look where the liquid intersects the markings on the hydrometer. ...
- Record the gravity reading.
Step 1: Determine the volume of alcohol in the drink. Step 2: Determine the total volume of the drink. Step 3: Divide the volume of alcohol by the total volume of the drink. Step 4: Multiply the result by 100 to get the ABV percentage.
How is alcohol proof measured? ›
3: In the United States, the system — established around 1848 — is a bit simpler: “Proof” is straight up two times alcohol by volume. So a vodka, say, that is 40 percent ABV is 80 proof and one that is 45 percent ABV is 90 proof. A “proof spirit” is 100 proof (50 percent ABV) or higher.
How to calculate pure alcohol content? ›
Calculating units
For example, wine that says "12% ABV" or "alcohol volume 12%" means 12% of the volume of that drink is pure alcohol. You can work out how many units there are in any drink by multiplying the total volume of a drink (in ml) by its ABV (measured as a percentage) and dividing the result by 1,000.
How is the level of alcohol measured? ›
It is calculated in grams per 100 mL of blood, so a BAC of 0.08 means your blood is 0.08% alcohol by volume. Using a breathalyzer, BAC is measured as grams per 210 Liters of breath (since the ratio of breath alcohol to blood alcohol is 2,100:1). What do you experience at different BAC levels?
Can you test ABV without hydrometer? ›
While most people will use a hydrometer to check the alcohol levels, you can also use a refractometer, which measures how light bends through a liquid to determine the density. Refractometers may not be as accurate, but they allow you to use drops of a sample rather than a large amount.
What tool is used to check ABV? ›
If you're on a budget, we'd recommend purchasing a brewing hydrometer for beer, wine, mead and cider. We'd also recommend a proofing hydrometer for measuring the ABV of spirits.
There are a few blood tests that can measure whether a person has been drinking. A blood alcohol concentration (BAC) test is commonly used to see if a person has been drinking recently. It is also called a blood alcohol content test. This test can find alcohol in your blood for up to 12 hours after drinking.
How to calculate the alcohol percentage? ›
The first step will be to multiply the 50ml measurement by 0.4 (40% ABV) which will equal 20ml of pure alcohol. This 20ml is then divided by 220ml (the total volume of the drink) which equals 0.09. Multiply this by 100 to get your ABV percentage which in this scenario is 9%.
How do you calculate ABV with a hydrometer? ›
The ABV can we worked out really simply by taking the start gravity from the finish gravity and dividing this figure by 7.362. For example the starting point for our wine is 1.080 and this ferments down to 0.990. The drop is 90 points. This divided by 7.362 is 12.23% ABV.
What is the most accurate way to test for alcohol? ›
While alcohol blood testing is the most accurate method of measuring the amount of alcohol in the body, alcohol can also be measured in samples of a person's sweat, hair, urine, breath, and saliva.
What is the formula for percentage proof? ›
Answer: The formula of Percentage is: Percentage = (Value/Total Value) * 100. Here, Value = 30 and Total Value = 120. So, percentage is (30/120) * 100 = 25%.
What is the formula for proof strength of alcohol? ›
From this, it follows that to convert the ABV expressed as a percentage to degrees proof, it is only necessary to multiply the ABV by 7⁄4. Thus pure 100% alcohol will have 100×( 7⁄4) = 175 proof, and a spirit containing 40% ABV will have 40×( 7⁄4) = 70 proof.
What proof is 5% ABV? ›
12 ounces of beer per serving, 10 proof or 5 percent ABV. 1.5 ounces of liquor or spirits per shot, 80 proof or 40 percent ABV.
What is 70% proof in ABV? ›
This value is still used as the British definition. A simpler ratio to remember is seven to four: 70° proof is 40% alcohol by volume. The "proof" system was introduced in the 18th century. The British claim that this term has a nautical background.
