According to the chemistry, calcium oxalate forms through the interactions of organic acids, calcium ions and carbonates, and the formation is increased in a CO2 rich environment. Essentially, increase the concentration of the individual compounds in beerstone and you have a higher probability of it precipitating out. However, the conventional wisdom in breweries is to add calcium to both the mash and boil to prevent calcium oxalate formation, i.e., oxalate is produced from having too little calcium in the brewing process. This seems counterintuitive to me as precipitates generally don't form when ion concentrations are too low. Additionally, adding calcium creates an environment where more of the beerstone forming compounds are present at higher concentrations, which should favor precipitation. Can someone help me out with this?