The time-dependent pH value in a fermentation
The pH is not corrected mathematically, it is stabilized chemically by addition of NaOH when the pH sensors get out of range. Your pH is controlled to be constant over the fermentation period (+/- a little bit).

The acid produced by the fermentation is neutralized by addition of NaOH to keep the pH constant. What you can calculate from the data you get is the rate of acid production. The moles of acid produced will equal the number of moles of NaOH added, to a good approximation. The pKa of H2PO4- is 7.2 and the pKa of acetic acid (a typical carboxylic acid) is 4.76, so the acid produced will be "strong" - i.e., fairly acidic in your medium, which appears to be aimed for about pH = 7 - and the NaOH is strongly basic, so they will balance out (approximately).

Interestingly, sodium acetate has a pH range of 8.5 - 9.9 in real life, according to SDS. Calculation is so much more pleasant, where you can calculate pH to three decimals and feel good about it (until you test it in real life and have to calibrate your meter, etc, etc.)