How To Read A Hydrometer

Learning how to use & read a hydrometer is essential when making your own beer or wine.  Using a hydrometer will let you know how much alcohol is in your beer and also when it is time to bottle. 

Follow these steps when using a hydrometer:

  1. Sanitize all equipment that will come in contact with your beer.
  2. Take a small sample of your beer or wine before you pitch your yeast.  We recommend using a Fermtech Wine Thief to take your sample.  This way, you can put your hydrometer directly into the thief for a quick read.
  3. Try and spin the hydrometer to remove any air bubbles that might be clinging to the hydrometer
  4. With the sample at eye level, look to see where the top of the sample crosses the markings on the hydrometer
  5. Write down the reading.  This is your Starting Gravity (SG).  This will tell you how much sugar is the wort.  
  6. Pitch your yeast and allow the beer or wine to ferment out completely. 
  7. Once your beer or wine appears to be done fermenting, take another hydrometer reading and write it down.  Your beer recipe or wine recipe likely has an estimated Final Gravity (FG).  If so, see if the reading you have taken matches up with the Final Gravity on your beer or wine making instructions.  Note: bottling your beer or wine before it has stopped fermenting can result in exploding bottles.
  8. Calculate your total alcohol content by using the following equation:  (Starting Gravity - Final Gravity) X 131.25

Example Calculation:

  • SG:  1.055
  • FG:  1.011

(1.055-1.011) X 131.25 = 5.8% ABV