In the distilled water pH vs color graph, your 2-row looks like an outlier. What about the wheat? Is it really that high all the time?
I made a note that the 2-row is Rahr 2-row. But I don’t know yet how universal these numbers are. They should be seen as a snapshot and are mostly to illustrate how low the correlation between color and base malt pH is.
In the discussion about using phosphoric acid to bring down pH, I'm not sure I'd agree that it wouldn't cause precipitation. A lot of the malt phosphate is as phytin which is insoluble and more limited in its exposure to the soluble Ca.
I agree with what Martin stated about this. And I have done some experiments that showed that phosphoric acid doesn’t change the pH more or less than lactic acid. However, there is always room for fluctuations.
Those are just a couple points I ran across this morning. I'm not being critical, just generating a discussion of your fine work.
I appreciate that. Since it is on the web I can easily update it once I get a better understanding about a particular topic.
So does this mean that it is the preferred acid for pH adjustment then? It doesn't supply flavor components like HCl, H2SO4 or lactic acid, and the phosphate is usable by yeast although you're saying this isn't a signficant benefit since there is plenty of phosphate in the mash anyway.
I have a strong influence by from German brewing where lactic acid is the preferred and the only acid that is used for pH correction. As a result I prefer lactic aicd and have been advocating its use. I only recently started phosphoric acid just to see if there is a difference. In fact my current double batch of KaIPA will be done with phosphoric and lactic acid as a side-by-side.
I have some 10% phosphoric acid I got from Northern Brewer, I may begin using it instead of lactic. Thanks Kai for providing an estimate for addition per gallon, relative to the other acids.
It’s also included in the table that shows how much to add per kg or lb of malt to lower the pH by 0.1. I used this number recently and the pH dropped a bit more than expected. I’m not sure what was up with that, though and don’t want to attribute it to increased Ca precipitation at this point.