May 18th, 2005

overmyhead
  • thaen

One more thing about gravity...

Forgot one small thing about gravity. If you take the gravity of the final wort (right before putting it into the primary fermenter, after the boil and the chill), and the gravity of the final fermented beer, you can use these values to determine the most important aspect of your beer: the alcohol content.

When taking these measurement, the beer needs to be flat (not carbonated), and you need to correct for the temperature of the liquid (since the temperature of water affects its volume and thereby its density). Well, neither of these things is strictly true (you can correct for them later), but most of the math you'll see on this subject assumes that you are making things easy on yourself.

The actual equation can be found in a million places online, or in any good beer book, and the one you want to use depends on what you want to find out -- alcohol by weight, by volume, percentage...