A hydrometer is an instrument that basically measures the density of liquids in relation to water. If is a very useful tool when making homebrew, and from its usage you can determine fermentation status (if it’s done or not), alcohol percentage, and the beers body which can help determine if you are within the recommended guidelines to beer style.

Accurately measure your homebrew with a quality hydrometer.

To calculate an approximate alcohol by volume of your finished homebrew: Original gravity minus Final Gravity times 129=your approximate homebrew alcohol by volume (ABV).

For example, a homebrew with an original gravity of 1.050 and a final gravity of 1.015 would be calculated as follows: 1.050-1.015=0.035X129=4.51% ABV

To take a hydrometer reading simply remove a sample from your wort and place it into the hydrometer jar. Make sure to use enough liquid so the hydrometer floats. Read your Original Gravity using the Specific Gravity scale on the hydrometer and write it down. Be sure to take your reading by indicating where the liquid actually intersects the stem of the hydrometer.

Take your Original Gravity reading before the yeast is pitched after brewing. Subsequent samplings/readings will take place before bottling your homebrew to ensure fermentation has stopped. Final gravity (FG) is taken just before bottling. Usually, your FG will be between one-third or one-fourth of your OG. For example, a beer in the 1.060 OG range should end up with a FG between 1.015-1.020. As a rule, water has a specific gravity of 1.000 when the sample is taken at 60F. Therefore, most hydrometers are calibrated at 60F, so you may have to adjust your gravity after taking it by using the below scale:

wort is 60F-No correction/adjustment needed
70F-add 1 point
77F-add 2 points
84F-add 3 points
95F-add 5 points
105F-add 7 points

Example: If wort temperature is 77F
OG is 1.050
Adjustment needed: 2 points
Correct OG is 1.052