Originally Posted by Kaiser
interestingly enough a lower mas pH may actually cause the yeast to have more trouble lowering the beer pH. This is due to increased phytase activity which increased the buffer capacity of the wort, so I have read.
I guess the idea would be that increased phytase activity would release more inorganic phosphate. Certainly mash at lower pH can hold more inorganic phosphate but the buffering capacity doesn't appear to change much. Mash at pH 5.3 saturated with respect to calcium and phosphate has a buffering capacity of 4 ppm as CaCO3 from the phosphate species. At pH 5.6 it can only hold half the phosphate but the buffering capacity only drops to 3.5. Never thought about this.