After correcting for this what sort of buffering numbers are you coming up with?
A question that gets right to the heart of things. Good!
Let me explain my overall procedure before I throw out any numbers. Anyone that has read my recent paper (with Mick Spencer -- ... Mash pH III ...) will know that we (i) made some measurements on distilled-water mash pH values and relative buffering capacities of a number of malts and flaked grains and (ii) we collated all the data we could find on these two quantities. Perhaps the most important thing we found was that there are significant
systematic differences (I won't call them errors, as I do not think these differences exactly rise to the level of errors) among each researcher when it came to the buffering capacities of Briess Caramel Malts. In the paper we discuss various possibilities for the differences, but that is not important here. What is important is that we were able to do a good job of normalizing the buffering capacities of these malts by applying a single multiplicative factor to the data from each researcher. Confirmation that such systematic difference existed was the result that the adjusted buffering capacities of dark roasted malts fell much more in line among the researchers, even though the data from these malts were not used in the normalization process. BTW, we
assumed a normalizing factor of 1.00 for the A.J. deLange data. The other multiplicative factors varied substantially -- from 0.86 (Walts data) to 1.62 (data of Kai Troester).
The importance of these findings are twofold. First, it is difficult, if not impossible, to assign an absolute buffering-capacity to a given malt, as the measured value appears to depend upon (as of yet unknown) differences in measuring techniques. Second, one cannot really know what the appropriate multiplicative factor is in a homebrew setting unless one has actual homebrew-setting data (thus the thread I recently started). Indeed, the exact multiplicative factor might very well be somewhat different from homebrewer to homebrewer.
Along these lines I'll mention that Kai Troester's data in his (in)famous 2009 paper show that crushed grains have an effective buffering capacity that is significantly less that that of pulverized grains.
With all that said, I currently find (based on the homebrewing data that has been posted on the recent thread) that a multiplicative factor of about 0.6 applied to the normalized values in the tables in my recent paper give the overall best agreement with the measured data. So for example, this would give an average buffering capacity of 27.3 for malt in the Pils/Lager/2-Row category. [BTW, my current comparison uses all of the water-chemistry science that you, Mr. deLange, have been arguing for in the forums for quite sometime. Charge must be conserved! I do choose, though, to assume a linear model of buffering (as described in my paper).]
I will say that I have identified one potential pitfall to assuming that a normalization factor is the whole story: perhaps there is a significant difference in distilled-water pH between pulverized and crush grain. I hope that Mick Spencer and I can experimentally address this.
Lastly, I'll say that all science is based on observation (clearly this is the physicist in me speaking here). To argue the benefits of any one mash-pH calculator over another without comparison to actual data (as is rife in this beer science forum) is folly at best. It can be amusing, though.
So there we go. A.J., if you have issue or questions with any of this, I'd certainly like to hear your thoughts. I'm more than happy to engage in a scientific discussion. Cheers!