Input
How to use this calculator
Enter grain weight, target mash temperature, grain temperature and water-to-grain ratio. The calculator derives mash water volume from the ratio and estimates a strike temperature for that mash-in. Keep the units consistent: kilograms, litres, Celsius and litres per kilogram.
This is a planning aid for the mash-in step. It does not include every possible loss, sparge volume, dead space or absorption term. Add those separately when planning the complete brew liquor volume.
How the calculation works
The public implementation calculates water = grain weight x water-to-grain ratio, then estimates strike temperature from target temperature, grain temperature and water volume using the same simple heat-balance style used by the page.
Actual mash water planning depends on grain absorption, tun dead space, transfers, evaporation and the volume you need in the kettle. Treat this output as the mash-in portion, not a complete water profile or liquor schedule.
Example calculation
For 5 kg of grain and a 3.5 L/kg ratio, the estimated mash water volume is 17.5 L. With a 66 C target and grain at 20 C, the page also returns a strike temperature estimate above the target.
Understanding the result
The water-to-grain ratio influences mash thickness, available volume and how much water remains for later steps. The target temperature is a process target, not a guarantee of conversion or final beer character.
Measure the mash after dough-in. If your actual volume or temperature differs, use the observation to tune your next batch rather than applying a universal correction.
Common mistakes
- Using total brewing liquor instead of mash-in water.
- Entering pounds with a kilograms field.
- Forgetting grain temperature.
- Assuming the ratio includes losses and absorption.
Frequently asked questions
What does L/kg mean?
It is the volume of mash water in litres for each kilogram of grain.
Does this calculate sparge water?
No. It estimates mash-in water and a strike temperature; sparge and system losses require separate planning.
Why can my real mash temperature differ?
Heat loss, mixing, grain moisture, vessel thermal mass and thermometer placement can all change the observed result.
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