Theoretical observation regarding Mash pH for DI Water vs. Mash pH for Zero Residual Alkalinity Water

[Silver_Is_Money]

If Kolbach is correct, and for the case of all else being equal, a mash carried out within deionized (or distilled) water and a mash carried out within mildly to even heavily mineralized water exhibiting the specific characteristic of achieving zero Residual Alkalinity (RA) should (theoretically at least) have the very same mash pH. This might be an interesting method for accomplishing quasi-Congress Mash pH analysis for malts via the use of waters that are a bit more "real world" representative of actual brewing water vs. using DI water, whereby the mineral water mash pH result should be the same as for DI.

An example of a nominally right close to zero Residual Alkalinity water (among myriads of potential other mineralizations which can achieve the same as to zero RA) might be:

Ca++ = 85.2 mg/L (ppm)
Mg++ = 8.3 mg/L (ppm)
Na+ = 30.4 mg/L (ppm)
Cl- = 100.7 mg/L (ppm)
SO4-- = 100.7 mg/L (ppm)
Alkalinity = 65.7 mg/L (ppm)
Bicarbonate = 80.1 mg/L (ppm)
Residual Alkalinity = ~0 mEq/L

5 gallons of the water above can be made up by adding ~ the following to distilled:
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2.30 grams Gypsum
3.95 grams CaCl2 (as the dihydrate), or 3.0 grams (as the anhydride, or anhydrous)
1.60 grams Epsom Salt
2.10 grams Baking Soda

 

[Silver_Is_Money]

The above mineralization does not take into effect dissociation constants. As such, to achieve a real world water with an alkalinity of an 'effective' ~66 ppm will likely take a pinch or so more Baking Soda (due to its poor dissociation). The specific quantity above 2.10 grams (as listed above) is actually variable with respect to the mash pH target. This is only being tossed out there for those who find a need to swat flies with atom bombs when it comes to being a bit more precise.

 

[Silver_Is_Money]

The logic behind this is that for the specific case of zero RA the induced downward pH shift as indicated by Kolbach for the presence of certain mEq/L's of combined Ca++ and Mg++ ions precisely 'opposite value' balances and thereby negates the upward pH shift induced by the extant mEq/L's of Alkalinity.

This in and of itself could be used to prove or disprove the 'linear output' validity of Kolbach's equation across a broad spectrum of Ca++ and Mg++ mineral mEq's. I'm on the side that says that the reality of the downward shift of such mineral mEq's will likely be proved to be in some fashion non-linear, leading to the rejection (and thereby replacement of) or modification of the Kolbach equation.

 

[Silver_Is_Money]

Would the verification or disproof of Kolbach be a worthy undertaking as the basis for a Masters or Doctoral thesis? Such is well beyond me at this stage in the game of life, but someone younger, in better health, and well more energetic might just want to pick up this ball and run with it. Overturning Kolbach would rock the foundation of much of brewing science.