Calculator
Mash & Sparge Water Calculator
It tells you how much water to heat for the mash and the sparge, how much wort you should collect before the boil and how hot your strike water should be.
Mash & Sparge Water Calculator: how to use it
- Enter the grain weight in kilos (or pounds) and the liters (or gallons) you want in the fermenter.
- Adjust your system's losses: boil-off per hour, what stays in the kettle and what the grain absorbs (1 L/kg, or 0.5 qt/lb, is typical).
- Enter your target mash temperature and the grain temperature (room temperature), in °C or °F. If you brew BIAB, check "all the water in the mash".
How it works
To end up with 20 liters (5.3 gal) in the fermenter, you have to start with quite a bit more: some water boils off, some stays in the kettle with the hop debris and some is absorbed by the grain. The calculator adds up those losses in reverse, from the fermenter back to the starting water. As for temperature, the grain is cold and pulls the water temperature down when you mix them: that's why you heat the strike water a few degrees above your mash temperature, and more so the less water you use per kilo of grain.
Frequently asked questions
How much water per kilo of grain?
Between 2.5 and 4 liters per kilo (1.2–1.9 qt/lb) for the mash is normal; 3 L/kg (1.4 qt/lb) is a good starting point. With BIAB you mash with all the water at once.
How do I know my kettle's boil-off rate?
Boil water for an hour, uncovered and at the heat you'll brew with, and measure how much it dropped. On home stoves it's usually between 2 and 4 liters (0.5–1.1 gal) per hour.
What is sparging?
Running hot water, at about 76 °C (169 °F), through the grain after the mash to rinse out the sugars left in it. With BIAB you don't sparge: you mash with all the water at once.
What temperature should I mash at?
Anywhere in the 62–68 °C (144–154 °F) range. Lower gives a more fermentable wort and a drier beer; higher gives more body and sweetness.