After a discussion about batter pH and how to measure it in hieperdepiep?s “how to add cognac to sour cream butter cake-batter” thread, I spoke with some friends of mine and two food scientists here at the local university about the best way to approach this issue. The consensus was that measuring the cake batter’s pH with a probe could be done, but it would not be an accurate measurement due to the way a pH probe measures the pH of a solution and that the oils, emulsions, and proteins in the batter would perturb the measurements. In a paper titled “Effects of sugars in batter formula and baking conditions on 5-hydroxymethylfurfural and furfural formation in sponge cake models.” published in Food Science International by Zhang, Yu-Yu, et al. 2012, a method describing how they measured the pH was described:
A ground sample (0.4 g) of cake was mixed with 20 mL of water and vortexed for 3 min. The mixture was held at ambient temperature for 1 h to separate solid and liquid phases. The pH of the supernatant was measured using a Thermo Orion 868 pH meter (Thermo Fisher Scientific, Inc., Pittsburgh, PA).
However, I did find another paper by Kilkus, S. where he measured the batter’s pH directly using a pH probe. Although Kilkus was able to measure the batter directly using a probe, it does make me wonder how accurate his measurements were because of the reasons mentioned above. After reading this paper I think this was a student’s paper for a class, but it was still an interesting read. Another issue with this paper was that the author did not specify which model of pH probe he used in his experiments.
Charles, with all of this being said, you might consider using the approach used by Zhang, Yu-Yu, et al. If you decide to purchase the pH probe you mentioned I would be interested to know how your tests go and which method you use.