I know that saponification is a chemical process and that all the various ingredients used in various recipes add complexity to the issue, but are there any general guidelines about what sort of color changes to expect? Are there there known chemical reactions that can be referenced? Or known ingredients that cause particular color changes?
I ask because while all of my previous batches (all 4 of them) lightened in color, my latest batch severely darkened - in fact, if I hadn't made the soap myself I'm not sure I would believed it was the same batch. I will say too that the residual soap left over in my mixing container, which I let sit overnight before cleaning up, did not darken at all...in fact it lightened like I thought the whole batch would (to the color of the thin layer seen in the cut bars below). I assume this is a temperature thing...but I never would have thought the difference could be so drastic!
I ask because while all of my previous batches (all 4 of them) lightened in color, my latest batch severely darkened - in fact, if I hadn't made the soap myself I'm not sure I would believed it was the same batch. I will say too that the residual soap left over in my mixing container, which I let sit overnight before cleaning up, did not darken at all...in fact it lightened like I thought the whole batch would (to the color of the thin layer seen in the cut bars below). I assume this is a temperature thing...but I never would have thought the difference could be so drastic!
