Thanks for the information. I wonder about the answer to the question you ask. I understand that regular soap ends up with a pH of 9-10. But does shaving soap end up with that high of a pH too? I wonder if shaving soaps may end up with a lower pH due to more fats/fatty acids being added to the lye, and if there is a significant difference among various shaving soap formulas. Don't know the answer, but with all the knowledge on this forum some members might be able to inform on this.
Because KOH and NaOH have alkaline properties, shaving soaps containing these ingredients need to retain their alkalinity. An excess of superfatting may lead to a soap texture that is too soft and mushy. It won't be a soap anymore.
Soaps with lower PH will go bad.