Calculating the anticipated pH drop across the boil

[Silver_Is_Money]

I dug through Wiley Online and came across this 1975 brewing research document (see link below). See Table XI on page 68 at the bottom left. It shows that in their tests:

1) A Wort which started the boil at a room temp. pH of 5.78 exited at pH 5.48. Drop = 0.30 pts.
2) A Wort which started the boil at a room temp. pH of 5.64 exited at pH 5.41. Drop = 0.23 pts.
3) A Wort which started the boil at a room temp. pH of 5.48 exited at pH 5.30. Drop = 0.18 pts.
4) A Wort which started the boil at a room temp. pH of 5.32 exited at pH 5.19. Drop = 0.13 pts.

The table data is said within the text to be sourced from no less than Narziss.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/j.2050-0416.1975.tb03663.x

FWIW, a linear regression of this admittedly sparse single data set provided this equation of best fit:
pH_Knockout = 1.80234 + (0.63774 * pH_Pre-Boil)

Note: The R^2 of the fit is 0.99540

 

[Silver_Is_Money]

The pre and post boil pH data seen above comes right close to converging upon a pre-boil value of 5.00 pH as the pH at which no further pH drop across the boil is witnesssed. If one takes the liberty to arbitrarily enter an extra data set with both column entries at 5.00 pH, and the data is re-regressed linearly, the R^2 fit improves noticeably to 0.9983, and the revised fit equation becomes:

pH_Knockout = 1.86336 + (0.62686 * pH_Pre-Boil)

 

[Silver_Is_Money]

I just integrated the above into the 'Kettle pH Made Easy' module (sheet/tab) within 'Mash Made Easy', and upgraded MME to version 10.55.

 

[Silver_Is_Money]

Of course the above regression equation can be quite easily and beneficially rearranged to reveal that:

Target_pH_Pre-Boil ~= (Target_pH_Knockout - 1.86336) ÷ 0.62686

When I realized that Target_pH_Pre-Boil is essentially the Mash_pH_Target this simple rearrangement was the key to simplifying my efforts to develop a vastly simplified means whereby to implement Knockout pH prediction, leading to Mash Made Easy version 10.85