Dave's Dreaded Homebrew Calculator

Dave's Dreaded Brewing

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The critical brewer will want to be able to discern subtle changes between brews when trying to duplicate or perfect that special recipe. This calculator provides a set tools to compute critical brew characteristics.

Key to understanding your brew is the measurement of Specific Gravity. Specific Gravity describes how much different than pure water your wort or brew is - in other words - how much of the Good Stuff is in your wort. Of particular interest is the amount of dissolved sugars. This will determine potential alcohol content of your beer. You should measure the specific gravity of your wort just after you brew - preferably when its cooled to near room temperature.

Specific Gravity is measured with an instrument known as a Hydrometer. It measures the density of wort relative to that of pure water - the higher the specific gravity ( > 1.000) the more dissolved solids are in your wort. Naturally, its not quite as simple as just measuring the specific gravity of the wort - you need to know the temperature as well. This is because the density of the wort varies with temperature. Hydrometers are calibrated to give accurate readings for liquids at 60 degrees F. Use this calculator to determine the actual specific gravity of your wort (known as Original Specific Gravity, or OG) at a particular temperature. While the corrected value may look only slightly different that the measured value, these small differences make a big difference in subsequent calculations.

Before Fermentation:
Actual Original Gravity, Original Extract, and Potential Alcohol:
Enter the wort temperature (degrees F):
Enter the Original Gravity:


The Actual Original Specific Gravity Is:
The Actual Original Extract Is:
(The percentage of (by weight) of solids disolved in the wort is know as Original Extract.)
Potential Alcohol determines the maximum percentage alcohol your brew could have.
Based on the specific gravtity, the maximum potential alcohol (by volume) is
After Fermentation:
Real Attenuation, % Alcohol, Calories:
Once your brew has fermented, a second specific gravity measurement is in order.
Enter the temperature of the fermented brew (degrees F):
Enter the measured final gravity of the fermented brew :


The Actual Final Gravity Is:
This reflects the actual % (by weight) of disolved solids in the brew.
The Real Extract is:
The difference between the Original Extract and the Real Extract determines the % alcohol.
The Real Attenuation of your brew is (% of solids converted to alcohol)
The % alcohol (By Weight) if your brew is
The % alcohol (By Volume) if your brew is
The calories in a 12 ounce bottle of your brew is