When we choose beers to enjoy, we choose based on a variety of characteristics such as color, taste, and alcohol content. Alcohol content, also called Alcohol by Volume (ABV), is usually displayed as a percentage and varies from beer to beer. But how do brewers figure out how much alcohol is in their beer? Read on to get a better look.
First thing’s first. The measurement of ABV is based on the comparison of the beer’s specific gravity before and after fermentation.
- Specific Gravity: A measure of the density of a liquid in relation to water (How Stuff Works).
Before beer becomes beer, it starts out as a liquid called “wort.” Wort is always going to have a higher density than the finished product. The ABV is directly related to the amount of sugar added to the wort before fermentation. Once yeast is added to the wort, it converts some of the sugars to ethyl alcohol.
In a Nutshell
Finding the specific gravity before and after fermentation determines how much sugar is left over and how much was converted to alcohol, and therefore, determines ABV.