So as promised here is a condensed summary of my easy water additions talk. More specifically easy water additions if you happen to live somewhere between Durban and Pietermaritzburg.
Municipal water provided in this area is quite soft, which does make modifying it to our needs quite easy. What follows is the water profile I use for our water, and over the years, the actual numbers have never been that far off.
- Calcium (Ca): 8.5ppm
- Magnesium (M): 3.5ppm
- Sodium (Na): 7.5ppm
- Sulfate (SO4): 4ppm
- Chloride (Cl): 10ppm
- Bicarbonate(HCO3): 36ppm
First we need to get our mash water to an adequate level of Calcium. To do this we add either 3g of CaSO4 (Gypsum) or CaCl (Calcium Chloride) per 20 liters of water. For hop accentuation go with the gypsum, for malt accentuation, go with the CaCl. Now that we have the minimum calcium level we want (roughly 85 ppm), we need to adjust the water further to make sure our mash pH is optimal. To do this you can do the following additions:
- Stout: 25-30 SRM: 9g bicarb. This pushes sodium level to 130ppm
- Dark Brown beers 20-25 SRM: Simply add 6.5g of bicarb to mash. Results in low sodium level or about 95 ppm
- Amber beers: 10-20 SRM: 3g bicarb. Barely raises sodium to 40ppm
- Light beers: 5-9 SRM: No more additions needed here
- Super Light <5 SRM: another 3g CaCl or 4g CaSO4
And that is all you need to have a healthy efficient mash!
Only with the light beers (9 SRM and lower) do I bother to modify the sparge water, and there I’ll add another 3g of CaCl or CaSO4 to help keep the pH down during the sparge.
Water chemistry in brewing is very complex, and a set of rules this simple is never going to cover everything. However this will get your mashes in the right zone, and is the beginning of playing with water profiles to affect your flavour profile. I suggest reading the mash pH chapter in John Palmer’s How to Brew, the 1st edition is free and is a very good step in the right direction.