agrazela
Well-Known Member
The mash Ca level is eventually diluted approximately 1/2 after sparging with untreated water. I believe it is further reduced by precipitation with malt phosphates (desired reaction to drive down RA) and possibly with oxalate (beer stone).
The amount of SO42- found in the finished beer is higher than can be accounted for by the gypsum addition alone, thus the malt must be contributing a few hundred ppm.
Finally, it is clear that malt adds a lot of chloride. It drives me nuts when I see the hand-wringing of some people expecting to find taste/mouthfeel differences changing chloride from 100 to 150ppm in their brewing liquor (see the myriad NE IPA threads).
Hmm, yes, OK, I am thinking like a no-sparge full-volume BIAB'er. I can see what you're saying about adding 1/2 your final volume as untreated sparge water, and that therefore there must be some sulfate being picked up, but also still some calcium being lost (but not nearly as much as I was thinking).
Trying to decide whether that changes what I want to do with my planned hellacious gypsum addition...
(I also agree it sounds like trying to finely control chloride would be like herding cats)