For any all grain brewing or simply mashing grain, it’s imperative to calculate the strike water temperature for grain mashing. Our strike water temperature calculator instantly works out the strike temperature for all grain brewing. Just put in how much grain you’re having, the temperature of the grain, the amount of water, your desired strike temperature. Hit enter and the page will instantly calculate strike water temperature.

Be sure to use the correct column for metric or imperial units, it works for both!

Strike Water Temperature Calculator

Metric Imperial
Mass of Malt kg lb
Temperature of Malt ⁰C ⁰F
Amount of Strike Water Litres Gallons
Target Mash Temperature ⁰C ⁰F
Strike Temperature ⁰C ⁰F

Calculating strike water temperature manually

Below we also present the strike water temperature formula in full with a complete explanation on how it works.

Strike temperature refers to the temperature the mash water needs to be at prior to adding grain so that, when the grain is added to the mash tun, the water cools down to the desired mash temperature instantly. Typically, the malted grain is at room temperature, so the strike water temperature will slightly higher than the desired mash temperature.

The key is to pour the grain into the water quickly while stirring gently to make sure that the grain doesn’t clump up. Then it’s just a matter of waiting and letting the mash process happen.

Calculating strike water temperature manually is quite easy, it’s just a simple formula. Of course the strike water temperature calculator above just this right away, but it’s always good to know the principles behind it.

The strike water temperature formula is:

Strike Temperature = 

Where the “thermo constant” refers to thermodynamic constant. The thermodynamic constant is:

  • Metric units – 0.41
  • Imperial units – 0.20

The thermodynamic constant is simply the specific heat of the grain. This is discussed further below.

If you’re using metric units, everything needs to be in kilograms, litres, and degrees Celsius.

If you’re using imperial units, everything needs to be in pounds, U.S. gallons, and degrees Fahrenheit.

The science behind strike water temperature calculations

The science here isn’t terribly difficult, it’s basically just a conservation of energy formula.

It’s no surprise that if something cold is added to something hot, the result will be a temperature something in between. That something in between will rely on three main things: the mass of the the cold thing, the mass of the hot thing, and the specific heat of each one (that is, how each gives up or accepts energy).

So, if there’s a lot of the cold thing, and a little of the hot thing, the temperature will come down much more than if it’s the other way around.

In relation to the strike water temperature formula specifically, all it is doing is working out how much the grain is going to cool down the strike water, so that it can be determined how hot the strike water needs be so that the resulting temperature is the desired mash temperature.

The specific heat used in the formula, is the assumed specific heat of grain. Specific heat refers the grains ability to transfer energy (compared to water). Of course it’s just an estimate since the exact specific heat will depend on exactly which grains are used, but, generally speaking, the specific heats listed above are about right.

And does it work?

Surprisingly, the formula (and therefore the the strike water temperature calculator) works!

Of course there are a few factors that can through off the calculations: the specific heat being slightly different, small differences in weights and volumes, how quickly the grain is poured into the mash tun all being examples. However, on all of our brew days, the calculated strike temperature gets us within less than half a degree (Celsius) of the target mash temperature. Pretty good!

With your brew ready to go, you’ll also need to calculate the IBU of your new batch of home brew. Then ferment, and work out the ABV of the beer. Use our other to home brew calculators to do that!