The final gravity or FG of a beer is the beer’s specific gravity once fermentation has completed. Once a brewer has measured the final gravity, it can be compared to the original gravity and the ABV or alcohol by volume can be calculated. The final gravity of a beer is typically taken using a hydrometer or refractometer. Specialty final gravity hydrometers are available to allow you to take a more accurate reading of your final gravity if desired.
Below are three different types of hydrometers used for taking the specific gravity readings of beer.