Original gravity, or OG, is your starting gravity before the yeast goes in. Wort into the fermenter is often warm, which makes the raw reading read low. Enter your reading and its temperature below for the true OG.
Correct your original gravity
When and how to take an OG reading
Take your original gravity after the wort is fully mixed in the fermenter and before you pitch yeast. Draw a sample, spin the hydrometer to shake off bubbles, and read at eye level where the liquid meets the scale.
If the sample is warmer than your hydrometer calibration temperature, correct it here. That corrected OG is what you will later pair with your final gravity to work out ABV.
What a normal OG looks like
Session beers sit around 1.035 to 1.045, standard-strength ales around 1.050, and strong beers 1.070 and up. If your OG comes in well under target, your mash efficiency or volumes may be off.
Once you have an accurate OG and FG, the ABV calculator turns them into your alcohol figure in one step.
Frequently asked questions
When do I take an original gravity reading?
Take it after the wort is fully mixed in the fermenter and before you pitch yeast. That is your OG, the starting point for working out ABV once fermentation finishes.
Why correct the OG for temperature?
Wort straight into the fermenter is often warmer than your hydrometer calibration temperature, which makes the raw reading too low. Correcting it gives you the true OG and a correct ABV later.
What is a typical OG?
Session beers sit around 1.035 to 1.045, standard-strength ales around 1.050, and strong beers 1.070 and up. Enter your reading and sample temperature for the corrected figure.
More homebrewing calculators
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