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In order to use this calculator, you’ll need to know the figure of your Tun Equivalent Water Volume. You’ll need to get this figure from the calibrate tun page.

If you’re mashing in a single vessel tun, with no internal heat source, you’ll need to get the temperature of the water you add to the tun just right to achieve a desired mash temperature.

Both the tun and the grains will absorb some heat, and the ambient temperature will have an effect.

You’ll need to add:

  • Grist Weight: the weight of all the grains in the mash tun
  • Grist temp: the temperature of all the grains in the mash tun - ambient or room temp usually
  • Ambient Temperature: temperature of the environment you’re mashing in.
  • Mash Tun Temp: temperature of the mash tun, probably around the ambient/room temp.
  • Mash Thickness: how thick you want your mash.
  • Mash Tun Eqv Volume: the heat capacity of your tun, based on the capacity of a litre of water. 0.7 = 0.7 litres of water equivalent.
  • Target Mash Temp: how hot you want to mash at.
  • Mash Tun Deadspace: how much deadspace you have in your tun.

The results will show you:

  • Strike Water Temp: temperature of the water you need to add to your tun to achieve the desired temperature mash.
  • Strike Water Volume: the volume of the water to add to the mash. This is simply: (Grist Weight x Mash Thickness) + Tun Deadspace. e.g. (10 x 1.25) + 2.5. Less thick mash = more strike water = lower strike water temp.


  • Integrate this into the recipe mash.

©2024 James Torr