Enter the weight of the grain and the absorption rate into the calculator to determine the grain absorption. This calculator can also evaluate any of the variables given the others are known.

Grain Absorption Formula

The following formula is used to calculate the grain absorption in brewing.

GA = (W * A) / V


  • GA is the grain absorption (liters) W is the weight of the grain (kg) A is the absorption rate (liters/kg) V is the volume of water (liters)

To calculate the grain absorption, multiply the weight of the grain by the absorption rate. Then divide the result by the volume of water. This will give you the amount of water absorbed by the grain during the brewing process.

What is a Grain Absorption?

Grain absorption refers to the process in brewing where grains absorb water during the mashing process. This is a crucial step in brewing as it affects the amount of water needed for the process and the concentration of the final product. The absorbed water is not recoverable, meaning it does not contribute to the final volume of the beer, which is why brewers need to account for grain absorption when calculating their water needs.

How to Calculate Grain Absorption?

The following steps outline how to calculate the Grain Absorption using the formula GA = (W * A) / V.

  1. First, determine the weight of the grain (W) in kilograms.
  2. Next, determine the absorption rate (A) in liters per kilogram.
  3. Next, determine the volume of water (V) in liters.
  4. Next, use the formula GA = (W * A) / V to calculate the grain absorption.
  5. Finally, insert the values of W, A, and V into the formula and calculate the result.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Weight of the grain (W) = 10 kg

Absorption rate (A) = 0.5 liters/kg

Volume of water (V) = 20 liters