Formula for ABV

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Alcohol is a waste product of the yeast. Want more yeast waste? Add more yeast food (sugar).

Sugar can come from a bag of sugar (this will dry the beer out because it is very fermentable), mashing grains, adding malt extract (essentially grains that someone else mashed for you, or countless other sources.

Try a beer calculator. They allow you to adjust what goes in and give an estimate of what comes out.
 
If you're interested you can work out your approximate ABV using this formula:

(OG - FG) X 131 = %ABV

so

(1.045 - 1.020) X 131 = 3.275

Don't forget you'll get a couple of extra gravity points from the priming sugar fermenting into alcohol and CO2 so you'll be close to 3.5%
 
Then when you get up around 1.060, you need to make sure your pitching enough yeast.
 
Og 1.045
fg 1.020

abv?

Be patient. Wait till your FG stops changing over a period of 3+ days.

If you're interested you can work out your approximate ABV using this formula:

OG - FG X 131 = %ABV

so

1.045 - 1.020 X 131 = 3.275

Don't forget you'll get a couple of extra gravity points from the priming sugar fermenting into alcohol and CO2 so you'll be close to 3.5%

Let me correct this.
(OG - FG) X 131 = ABV
If you put the original formula into a calculator with your figures, you will get OG = 1.045
FG X 131 = 133.62
%ABV = 1.045 - 133.62 = -132.155
This is obviously wrong.

-a.
 
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