When you have a beverage that you don’t know what the alcohol content of, either because you didn’t take an original gravity reading or you lost your notes or whatever, a way to find that out is with a Spirit Indication Test.


  1. Take a gravity reading with your hydrometer.  Write this down.
  2. Take the temperature of your sample.  Write this down.
  3. Boil your sample down to half.  So if you had 6 ounces, boil it down to 3 ounces.
  4. Add distilled water back to your sample so you are back to the original amount.  So if you had 6 ounces, and you boiled away 3 ounces, you would add 3 ounces of distilled water.
  5. Cool the sample down to close to your original temperature (within a couple of degrees is fine.)
  6. Take the gravity reading once again. Write this down.
  7. Take the temperature once again.  Write this down.
  8. Taking the numbers you jotted down in steps #1, 2, 6 & 7, and plug them into the form below to find out the ABV.


Hydrometer calibration temperature (should be on the hydrometer itself): F C
Initial reading (from step #1):  
Initial temperature (from step #2): F C
Final reading (from step #6):  
Final temperature (from step #7): F C
Percent alcohol by volume:

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