How to Calculate Alcohol Content in Wine

by Damian Rossi ; Updated September 28, 2017

Finding the alcohol content of wine is easy with a hydrometer.

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Knowing the alcohol content of your homemade wine can save a night from being disastrous. If you have produced your own homemade wine, then you may want to know the alcohol content. The alcohol content in wine can range from as little as one percent to 20 percent. You can determine the alcohol in your wine with a simple tool called a hydrometer. Knowing the amount of alcohol in your wine can give you the heads up you need when it comes to how much you can drink.

Drop the hydrometer into your wine before fermentation. Once the hydrometer has settled and is floating, record where the surface of the liquid crosses the gravity scale.

Place the hydrometer in your wine at the end of fermentation and record the specific gravity. The reading will be different, because as yeast metabolizes sugar, it produces ethanol and carbon dioxide. The carbon dioxide is released and the liquid that is left behind become less heavy.

Calculate the amount of alcohol in the wine by using this formula.

Percentage of alcohol = ((1.05 x (OG – TG)) / TG) / 0.79

OG is the original gravity reading that you took. TG stands for terminal gravity or the reading you took at the end of fermentation.

For example, if the original gravity was 1.06 and the terminal gravity 1.01, the equation would read:

Percent alcohol = ((1.05 x (1.06 – 1.01))/1.01) / 0.79

Therefore, the wine’s alcohol percentage is 6.6.


  • A refractometer may also be used to determine alcohol content to a more precise measure. However, a refractometer is more expensive then a hydrometer.

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About the Author

Damian Rossi has been a freelance writer since 2008, specializing in fitness and wellness. He graduated with a bachelor’s degree in exercise science from Texas Tech University. Rossi is pursuing his master's degree in sport psychology from Texas Tech University.