Strike Water Temperature Calculator
Hit your mash temp on the first pour
Strike water temperature is the temperature your infusion water needs to be before you add it to the grain. The cold grain absorbs heat from the water, dropping it to your target mash temperature. Get this wrong and you're mashing too hot or too cold — alpha and beta amylase work at different temperatures, so it matters.
The calculation is simple: more grain relative to water means you need hotter strike water. Colder grain means you need hotter water. This calculator uses Palmer's heat balance equation — the same one BeerSmith and Brewfather use.
Strike Water Temp
heat balanceEnter your target mash temperature, grain temperature, and mash thickness to find the strike water temperature.
If you're doing a step mash with decoctions or infusion steps, the first rest uses this equation. Subsequent rests use a different calculation (adding boiling water to raise temperature), which the recipe builder handles automatically.
How We Calculate It
Where r is mash thickness in L/kg and 0.41 is the grain/water heat capacity ratio.
The 0.41 constant is the ratio of grain's specific heat capacity to water's (approximately 1.71 kJ/kg·K ÷ 4.18 kJ/kg·K). It tells you how much less heat grain holds compared to water at the same temperature — which is why you need strike water hotter than your target: the grain steals heat.
Target mash temp 67°C, grain at 20°C, thickness 3.0 L/kg:
67 + (0.41 ÷ 3.0) × (67 − 20) = 67 + 0.137 × 47 = 73.4°C
You need strike water at 73.4°C (164.1°F) to land at your 67°C target mash temperature.
Mash Thickness
Mash thickness (also called the water-to-grain ratio) is how many liters of water you use per kilogram of grain. A typical single infusion mash runs 2.5–4.0 L/kg. Thinner mashes (more water) are more temperature-stable and easier to control. Thicker mashes (less water) can improve efficiency but require more precise strike temperatures.
Typical Mash Thicknesses
2.0–2.5 L/kg — Thick mash, traditional British ale style
2.5–3.5 L/kg — Standard single infusion, most styles
3.5–4.5 L/kg — Thin mash, BIAB (brew-in-a-bag)
Grain Temperature
If your grain is stored in a cold garage (5–10°C) versus a warm kitchen (22°C), your strike temperature changes by several degrees. It's worth measuring actual grain temp rather than guessing room temperature — especially in winter. The recipe builder defaults to 20°C (68°F), which is fine for grain stored indoors.
See all the numbers come together in real time.
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