Mash Water & Sparge Water Calculator
Type in your variables and constants to calculate mash water, sparge water, and strike temperature for your brew day.
Calculate mash water, sparge water, and strike temperature
This calculator estimates the water volumes needed to hit your batch size after grain absorption, boiloff, shrinkage, trub loss, and equipment loss.
Example water-volume plan
For a 5 gallon batch with 10 lb of grain, set your mash thickness, boil time, boiloff rate, and losses. The result gives a practical mash-water and sparge-water plan for brew day.
- Enter 5 gal batch size and 10 lb grain bill.
- Set mash thickness, boil time, trub loss, equipment loss, and boiloff rate.
- Use the result to prepare strike water and sparge water before heating.
Watch for: Once you measure real kettle losses, update the constants so future batches match your system.
Frequently asked questions
What is sparge water?
Sparge water rinses sugars from the grain bed after the mash so you can collect enough wort for the boil.
Why does grain absorption matter?
Grain holds back some mash water, so absorption affects how much sparge water you need to reach the kettle volume.
Should I adjust the constants?
Yes. Boiloff, trub loss, and equipment loss vary by system, so update them when you have measured values.
Does this replace water chemistry planning?
No. This calculator handles volumes and strike temperature; use the water chemistry calculator for ions, salts, and mash pH estimates.
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