How to calculate Ca concentration needed for mash?

[ShootsNRoots]

For a given recipe how would one calculate the concentration of Ca needed for the mash.

 

[jmf143]

The recommended range for Ca is 50 - 150 parts per million. 1 gram of Calcium Chloride dissolved in 1 gallon of water provides 72 ppm of Ca (and 127 ppm of Cl). 1 gram of Gypsum dissolved in 1 gallon of water provides 60 ppm of Ca (and 147 ppm of SO4). As you will be using more than a gallon of water in your mash, your ppms will be diluted linearly i.e. 1 gram in 3 gallons would be 33% of the ppm, 1 gram in 5 gallons would be 20% of the ppm etc.

Figure out the volume of water that you will use in your mash and dose accordingly. Using either Calcium Chloride or Gypsum will work, keeping in mind you will also be getting its accompanying Chloride or Sulfate.