Hi all so the recipe I have is for crockpot . I have seen several videos where they added borax is this something I should do? I have The everything soapmaking book and nothing about borax in it, I am not really crazy about adding it if I don't have to. TIA
It's probably just as a source of sodium to make the product more viscous. There are other choices for doing that, if it's even something you want to do.
Conceivably borax could be used to make the soap more alkaline to be a better cleaner, as has been done with laundry soaps.
I've seen it mentioned as a pH adjuster for too-alkaline soap, but adding alkali such as borax cannot reduce the alkalinity of a soap solution, even if it does cause the reading on a pH meter to go down a little. The only way it might work to adjust alkalinity is if you saponified lye-heavy (to make the rxn go faster), then neutralized the excess with an acid (such as citric), but used too much acid and needed to restore alkalinity.