Fermentation Yield Calculator

Because ABV is a ratio of alcohol to total volume, and both the total sugar available to ferment and the total wash volume scale up together as Wash Volume increases -- a 100-liter batch and a 25-liter batch at the same Sugar Concentration ferment out to the same percentage, the larger batch just produces four times the total Alcohol Volume in mL. Wash Volume only affects the absolute quantities (Total Sugar, Theoretical Ethanol, Actual Ethanol), never the ABV percentage itself.

Distiller's yeast strains bred specifically for high alcohol tolerance and clean conversion commonly achieve somewhere in the 80-90% range of the theoretical maximum under good conditions -- proper temperature, adequate yeast nutrient, and a well-pitched starting cell count. Baking yeast or an underpitched, nutrient-starved, or temperature-stressed fermentation can fall meaningfully below that range, so treat 85% as a reasonable planning default rather than a guarantee.

Theoretical Ethanol applies the Gay-Lussac stoichiometric maximum -- the most ethanol that could possibly result from the sugar present, assuming perfect conversion with zero loss. Actual Ethanol scales that theoretical figure down by Yeast Efficiency, since real fermentation always falls short of the theoretical ceiling due to yeast maintenance metabolism, incomplete attenuation, and byproducts other than ethanol and CO2 that consume some of the available sugar.

Within the range this calculator covers, yes -- Sugar Concentration is one of the two inputs (along with Yeast Efficiency) that directly raises Expected Wash ABV. In real fermentations, though, pushing sugar concentration too high can stress or stall the yeast through osmotic pressure before it finishes converting, which this calculator doesn't model -- very high starting gravities often need a specialized high-tolerance yeast strain and careful nutrient management to actually reach their theoretical ABV.