Mash Water Volume Calculator

Work out mash water volume instantly with clear inputs, formula shown and shareable results.

About Mash Water Volume Calculator

Strike water is grain weight times mash thickness, typically 2.5-3.5 litres per kilogram. Grain retains around 1 litre per kilogram, and the tun's dead space holds more, so first runnings are always well below the water added. Grain itself occupies about 0.67 litres per kilogram, which sets the tun volume needed.

Formulas

Strike water

Strike water = grain weight x mash thickness

Runnings

First runnings = strike water - grain absorption x grain weight - dead space

Worked example

With the default values below, Mash Water Volume Calculator returns Strike Water Volume of 15.000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Grain Weightminimum 0 kg: 5 kg
Mash Thicknessminimum 0.1 L per kg: 3 L per kg
Grain Absorptionminimum 0 L per kg: 1 L per kg
Mash Tun Dead Spaceminimum 0 L: 1 L

Results

Strike Water Volume: 15.000
First Runnings Recovered: 9.000
Water Absorbed By Grain: 5.000
Total Mash Volume: 18.350

Step by step

1Values used
2Strike water
3Runnings
4Strike Water Volume= 15.000
5First Runnings Recovered= 9.000
6Water Absorbed By Grain= 5.000
7Total Mash Volume= 18.350

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Does mash thickness affect the beer?

Yes. Thicker mashes favour beta-amylase and produce more fermentable wort with better protein degradation; thinner mashes favour alpha-amylase and extract more efficiently.

Why does grain absorption vary?

With crush, husk content and how thoroughly the grain bed is drained. Measure your own figure by mass balance over several brews rather than assuming a book value.