Teach Soap

I am having a great time soap making, but have had a problem I haven't seen addressed on any site. On several batches where I have used an ingredient that colors the soap (vanilla FO on some and orange palm oil on another batch) everything has gone beautifully, but on the finished bars the outside has dried but on breaking the bar apart, the inside is still soft. On some round vanilla scented bars, it looks like a peanut butter cup when the bar is broken in half, dark on the outside and caramel colored inside. The quality of the bars doesn't seem to be affected., except that they tend to break apart easier than the plain soap I have made. The air is very dry here in New Mexico, especially now with the heater in use, so I am wondering if the bars are drying so quickly on the outside that it is forming a sort of protective layer, keeping the inside from drying out. Does that make sense to anyone, and do you have any ideas for correcting this? This has happened on both plain cold process, and on a few rebatched pounds.

How long are you letting your bars cure? I live in a very dry desert and the outside dries out very quickly. As far as vanilla based soaps, the darkening you see is from oxygen reacting with the soaps. Since the air hasn't gotten to the inside yet, vanilla based soaps tend to be lighter on the inside til they are exposed to air or cut.

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Irena
Closed minds are like faulty parachutes; they refuse to open.

The original vanilla bars are about 10 weeks old. Very mild and nice to use. This has also happened on some rebatched bars from a different recipe that are about 3 months old, counting from the original making, and about 11 weeks from when I rebatched and added some tea oil and peppermint oil. Also had the same result on some soap rebatched with Amber Wood FO. I expected the vanilla to darken, and wasn't surprised by the amber wood darkening, but the extreme difference in the outside and inside color was unexpected. I think you are right that air isn't getting to the inside, but I'm not sure it ever will because the outside of the bars is so hard and dry now.

Did your soap go through a full gel? A couple of mine that had partial gel look like what you are describing.

I'm not sure if the vanilla bars went through full gel; because there is milk in them I didn't wrap them up tightly to insulate, just put a thin box over them. The bars were molded in 3" PVC pipe and cut after about 36 hours. The soap was all the same color when cut, then the outsides turned dark brown. AFter about 8 weeks or so I broke one in half, and that is when I discoverd the "peanut buttter cup" look. The other bars are rebatched from a plain soap recipe, and the original bars before shredding up were great. I'm sure that they went through gel. Because we keep our house quite cold, I use a flat insulated bag (such as pizza delivery uses) to insulate my soap after pouring it in the mold. This has worked great, and I think it must advance the saponification a bit, because my soap is already very mild when I cut it in the next day or so. I don't do this for soap with milk or honey in it though.

If there is milk in your batch, it most likely gelled, due to natural sugars in the milk. Vanilla based soaps will always be darker on the outside.

_________________
Irena
Closed minds are like faulty parachutes; they refuse to open.