Soap tastes sour?

[McSpin]

Sorry, I must have missed it, or wasn't paying attention since I assumed that would be the case.

So, if I have a recipe that after 4 weeks, tests at 10.2 pH, on a regular basis, then it would seem to me that pH testing would tell me if a future batch of this recipe was safe, since if the buffer is used up and lye is present, the pH should be higher.

 

[The Efficacious Gentleman]

If you could reliably test it, I would say so. Having a known benchmark of a recipe and making it in the same way (eg always distilled water) would be the only way that a pH test could tell you if your soap is safe. Otherwise you don't know just from the pH if it is safe or not.

Which is why I zap test

 

[McSpin]

I do have the equipment and supplies. I have electronic pH meters, the calibration solutions and distilled water. I think I will test all my soaps just to get an idea of how much pH actually varies with mine. If I have time, I'll purposely make a lye-heavy soap and then see what happens to the pH over time. I have close to 40 soaps sitting here from different recipes, so now is probably a good time to do this.