How hot should my strike water be?
Enter your grain weight and temperature, your water-to-grain ratio and the mash temperature you want. The strike water calculator gives how hot to heat the water and how much to use.
- Strike water temperature
- 165.4
Heat the strike water to 165.4 degrees (°F with US units, °C with metric).
- Strike water volume
- 12.5
- Strike water (US gallons)
- 3.13
Strike water temperature: 165.4. Heat the strike water to 165.4 degrees (°F with US units, °C with metric).
How to calculate
Works out the strike water temperature and volume for an all-grain mash from the grain weight, the water-to-grain ratio, the grain temperature and the target mash temperature (Palmer’s infusion equation).
Example with the default inputs (Units US, Grain weight (lb) 10, Water to grain (qt/lb) 1.25, Grain temperature (°F) 68, Target mash temperature (°F) 152): Heat the strike water to 165.4 degrees (°F with US units, °C with metric).
Method: Tw = (c ÷ r)(T2 − T1) + T2, c = 0.2 with qt/lb and °F or 0.41 with L/kg and °C; volume = r × grain weight.
- The mash tun is preheated, so it takes no heat from the water; a cold tun needs hotter water.
- 0.2 and 0.41 are the grain’s heat capacity relative to water in each set of units; the two systems can differ by a few tenths of a degree.
- All the strike water goes in at once (a single infusion).
Worked examples
Each example is checked against the calculator on every build.
- Units US, Grain weight (lb) 10, Water to grain (qt/lb) 1.25, Grain temperature (°F) 68, Target mash temperature (°F) 152 gives Strike water temperature 165.4, Strike water volume 12.5, Strike water (US gallons) 3.13.Source: John Palmer, How to Brew, online edition, Calculating Strike Water Temperature (Tw = (0.2 ÷ r)(T2 − T1) + T2; r in qt/lb, °F), http://howtobrew.com/book/section-3/how-the-mash-works/calculating-strike-water-temperature
- Units Metric, Grain weight (kg) 5, Water to grain (L/kg) 2.5, Grain temperature (°C) 18, Target mash temperature (°C) 67 gives Strike water temperature 75, Strike water volume 12.5.Source: Home Brew Answers, Calculating Strike Water Temperature For Mashing (Tw = (0.41 ÷ R)(T2 − T1) + T2 with L/kg and °C; example (0.41 ÷ 2.5) × (67 − 18) + 67 = 75 °C), https://homebrewanswers.com/document/calculating-strike-water-temperature-for-mashing/ (shown there as 75 °C)
- Units US, Grain weight (lb) 12, Water to grain (qt/lb) 1.5, Grain temperature (°F) 60, Target mash temperature (°F) 154 gives Strike water temperature 166.5, Strike water volume 18, Strike water (US gallons) 4.5.Source: John Palmer, How to Brew, online edition, Calculating Strike Water Temperature (Tw = (0.2 ÷ r)(T2 − T1) + T2; r in qt/lb, °F), http://howtobrew.com/book/section-3/how-the-mash-works/calculating-strike-water-temperature
How it works
Palmer’s initial infusion equation:
Tw = (c ÷ r) × (T2 − T1) + T2
- Tw: strike water temperature
- r: water-to-grain ratio
- T1: grain temperature
- T2: target mash temperature
- c = 0.2 with US units (r in quarts per pound, temperatures in °F) and c = 0.41 with metric units (r in liters per kilogram, temperatures in °C)
Strike water volume = r × grain weight, in quarts (US) or liters (metric). With US units the volume is also shown in US gallons: quarts ÷ 4.
The two constants are separate conversions, so the same mash typed in US and in metric units can differ by a few tenths of a degree. The calculator uses each as published and does not convert between the two systems.
Inputs and limits
| Field | US | Metric |
|---|---|---|
| Grain weight | 0.01 to 10,000 lb | 0.01 to 5,000 kg |
| Water to grain | 0.1 to 10 qt/lb | 0.1 to 20 L/kg |
| Grain temperature | −40 to 200 °F | −40 to 93 °C |
| Target mash temperature | 32 to 212 °F | 0 to 100 °C |
Typed values are read as exact decimals and every step is exact. The temperature is shown rounded half up to 1 decimal, volumes to 2 decimals. A grain temperature above the mash temperature is allowed; the strike water then comes out cooler than the mash.
Assumptions
- The mash tun is preheated and loses no heat.
- All the strike water is added at once.
Worked examples by hand
10 lb at 68 °F, 1.25 qt/lb, 152 °F mash: Tw = (0.2 ÷ 1.25) × (152 − 68) + 152 = 0.16 × 84 + 152 = 165.44 °F, shown as 165.4. Volume = 1.25 × 10 = 12.5 qt = 3.13 gal.
5 kg at 18 °C, 2.5 L/kg, 67 °C mash (the Home Brew Answers example): Tw = (0.41 ÷ 2.5) × (67 − 18) + 67 = 0.164 × 49 + 67 = 75.036 °C, shown as 75.0. Volume = 12.5 L.
12 lb at 60 °F, 1.5 qt/lb, 154 °F mash: Tw = (0.2 ÷ 1.5) × 94 + 154 = 12.5333 + 154 = 166.53 °F, shown as 166.5. Volume = 18 qt = 4.5 gal.
Other questions people ask
How do I calculate strike water temperature?
With Palmer’s initial infusion equation: Tw = (0.2 ÷ r)(T2 − T1) + T2, where r is quarts of water per pound of grain, T1 the grain temperature and T2 the target mash temperature in °F. For 1.25 qt/lb, grain at 68 °F and a 152 °F mash: 0.16 × 84 + 152 = 165.4 °F.
What is the metric version?
Tw = (0.41 ÷ r)(T2 − T1) + T2 with r in liters per kilogram and temperatures in °C. For 2.5 L/kg, grain at 18 °C and a 67 °C mash: 0.164 × 49 + 67 = 75.0 °C.
Why is the strike water hotter than the mash?
The grain is colder than the mash, so it takes heat from the water when you mix them. The water must start hotter by the amount the grain will absorb, which depends on how much water there is per pound or kilogram of grain.
What water-to-grain ratio should I use?
Many brewers use 1 to 2 quarts per pound (about 2 to 4 L/kg). A thicker mash (less water) needs hotter strike water for the same mash temperature, because less water carries the heat.
Why did my mash come out cooler than planned?
The equation assumes the mash tun is already warm. A cold tun absorbs heat too, so preheat it with hot water, or heat the strike water a few degrees more and let it cool to the target before adding the grain.