About

Precise calculation is the difference between a high-quality spirit and a failed fermentation. This tool serves hobbyist distillers by aggregating essential calculations into one interface. It handles Potential Alcohol by Volume (ABV) estimation based on specific gravity, corrects hydrometer readings for temperature variance, and calculates the necessary yeast pitch rate to avoid stressed fermentation (which produces off-flavors).

The wash calculator utilizes a database of fermentable ingredients to predict Original Gravity (OG) before you even heat the water. This allows for the theoretical construction of mash bills to hit target specific gravities. Temperature correction uses standard calibration data (usually 60°F/20°C) to adjust density readings, ensuring that yield estimations remain accurate regardless of working conditions.

Formulas

Alcohol by Volume is calculated using the standard difference in density between the Original Gravity (OG) and Final Gravity (FG):

ABV = (OG − FG) × 131.25

Temperature Correction for Hydrometers (Calibrated at 60°F):

CG = SG x (1.00130346 − 0.000134722124T + 0.00000204052596T² − 0.00000000232820948T³)

Reference Data

Ingredient	PPG (Points/lb/gal)	Potential Yield	Type
White Sugar (Sucrose)	46	High	Simple Sugar
Dextrose (Corn Sugar)	46	High	Simple Sugar
Dry Malt Extract (DME)	44	Medium	Malt
Liquid Malt Extract (LME)	36	Medium	Malt
Molasses	36	Medium	Sugar Byproduct
Honey	35	Medium-High	Natural Sugar
Flaked Corn (Maize)	33	Medium	Grain (Adjunct)
Malted Barley (2-Row)	35	Medium	Grain (Base)
Rye Malt	29	Low-Medium	Grain
Wheat Malt	37	Medium	Grain
Maple Syrup	30	Medium	Natural Sugar
Brown Sugar	46	High	Simple Sugar

Frequently Asked Questions

PPG stands for "Points per Pound per Gallon". It represents the density contribution of 1 pound of a specific fermentable dissolved in 1 gallon of water. For example, sugar with 46 PPG will increase the specific gravity of 1 gallon of water from 1.000 to 1.046.

Hydrometers are calibrated to read specific gravity accurately at a specific temperature (usually 60°F or 20°C). If your wash is warmer, the liquid is less dense, causing the hydrometer to sink lower and give a falsely low reading. Correction is vital for accurate ABV calculation.

Under-pitching yeast causes "lag time" where bacteria can infect the wash. It also stresses the yeast, leading to the production of fusel alcohols (giving a "hot" or solvent-like taste) and esters that may not be desirable in the final spirit.

For simple sugars (dextrose, sucrose), efficiency is nearly 100%. For grains (corn, barley), this calculator assumes a standard homebrew efficiency of roughly 75%. You may need to adjust quantities if your mashing process (conversion of starch to sugar) is more or less efficient.