Calculate grain water absorption from grain weight and absorption rate, or total water absorbed by grain type in liters and gallons.

Multiply grain mass by its measured or estimated retention rate.

Estimate liquid retained after your chosen draining or squeezing process. Calibrate rates to your grain and equipment; all gallons are US gallons.

Related Calculators

Grain Absorption Formula

The following formula is used to calculate the volume of water absorbed by grain during mashing (grain absorption).

GA = W ร— A

Variables:

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

To calculate the grain absorption (volume absorbed), multiply the weight of the grain by the absorption rate. The result estimates liquid retained after the chosen draining process. All gallons in the calculator are US gallons. The grain-bill tool sums each grain mass multiplied by its editable rate; every type starts at the same 1.0 L/kg estimate, not a proven grain-specific coefficient.

What is 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. For this estimate, retained liquid is the liquid left with the spent grain after your chosen draining or squeezing process. Recovery varies with the process, so calibrate the retention rate to your equipment.

How to Calculate Grain Absorption?

The following steps outline how to calculate the Grain Absorption using the formula GA = W ร— A.

  1. First, determine the weight of the grain (W) in kilograms.
  2. Next, determine the absorption rate (A) in liters per kilogram.
  3. Next, use the formula GA = W ร— A to calculate the grain absorption.
  4. Then, multiply W by A to find GA (the volume of water absorbed) in liters.
  5. If you need to solve for a different variable, rearrange the formula (for example, A = GA / W or W = GA / A).

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

Grain absorption (GA) = 10 ร— 0.5 = 5 liters