United KingdomTier 2
Strike and sparge water calculator
Grain weight and target mash temperature in. Strike water temperature, mash water and sparge volume out.
Free·No sign-up·Last checked 2026-08-27
Formula
Mash water (L) = grain_kg × thickness (L/kg)
Strike temp (°C) = target mash + (0.4 ÷ R) × (target mash − grain temp), R = L/kg
Sparge water (L) = total water − mash water
Worked example. 4.5 kg grain at 2.6 L/kg, 21°C grain to 67°C mash → strike at 74.1°C, 11.7 L mash water.
Method
Metric-native strike temperature formula
The 0.4 constant is grain's specific heat expressed as a dimensionless fraction of water's — the same physical ratio behind the imperial "0.2" constant, which additionally bakes in a quart-to-pound conversion that doesn't apply once everything is in litres and kilograms.
Questions
The grain starts at room temperature or colder and pulls the mash temperature down when it's mixed in. Strike water is heated above the target so the mixed result lands where you want it.
2.6 L/kg (about 1.25 quarts per pound) is a common all-purpose default. Thinner mashes (up to about 3.1 L/kg) can improve enzyme access for some recipes; thicker mashes (down to about 2.1 L/kg) are sometimes used for decoction or high-gravity brews.