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Mash and Sparge Water Calculators

When you first switch to all grain brewing, you may get a bit overwhelmed with some of the new calculations you’ll need to do to figure out how much water you will need to mash and sparge and what the temperature of the water needs to be for each step. Don’t worry! You can use the following mash and sparge water calculators to figure it out easily in advance. Make a note of the amounts and temperatures on your Brew Day Worksheet for an easy brew day!

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Mash In: Strike Water Volume

Mash In Strike Water Volume Formula: ____  lbs grain x .31 gal/lb = _____  gallons of strike water


Mash In: Strike Water Temperature

Mash In Strike Water Temperature Formula: SWT = (0.2/((SWV*4)/GW))*(DMT-GT)+DMT

  • SWT = Strike Water Temperature (F)
  • SWV = Strike Water Volume (Gallons)
  • GW = Grain Weight (lbs)
  • DMT = Desired Mash Temperature (F)
  • GT = Grain Temperature (F)

Mash Out: Water Volume

Mash Out Water Volume Formula:  WV = (TT – CT)(.2GW + CWV)/(210 – TT)

  • AWV= Added Water Volume (Boiling, but you will lose a degree or two, so we adjusted to 210 in the formula)
  • TT = Target Temperature of the Mash
  • Current Temperature of the Mash
  • GW = Grain Weight (lbs)
  • CWV = Current Water Volume (Water you have already added to the mash)

Sparge Water Volume

Sparge water:   _____ lbs grain x .28 gal/lb = ____  gallons at 168-170 °F


Total water needed: _____.    The night before you’re planning to brew, treat all water with Campden tablets at the rate of ¼ tablet per 5 gallons to remove chlorine and chloramines.  Other salts or mineral scan also be added now if desired.

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