I know this topic has been discussed a lot and I just want to share some recent observations.
So I use SoapQueen's cupcake soap recipe to make a lot of cupcake soap, same exact recipe, didn't change a bit.
Last fall I observed the cupcake soap I made, some batches got ash and some didn't. Made them the same temp, no insulation, but different FO and color. Darker color ones get ash and lighter color ones don't.
Last month I want to do a more controlled experiment on to proof if color effects ash. Made a batch, divided into 2 halves, one colored with copper mica and red oxide to medium shade (pretty dark), and the other just light green mica. Again, same temp and no insulation, both using silicone molds but different FO. Next day, copper red ones ended up perfectly fine, no ash at all, but the light green started having white dust all over the top. Popped them all out the molds and set them up to cure. 3 more days later, copper red ones are still fine but the light green ones are now covered with a layer of white ash and migrated to the sides.
Experiment #3, made a batch, colored it light green mica again, same FO, half of them made into cupcake, the other half made into plain oval shape bar soap. Both molds are silicone. Next day, cupcake ones are covered with ash on the top, but the ones in individual oval silicone molds just have tiny little white dust here and there.
Conclusion #1, color probably has nothing to do with ash.
Conclusion #2, recipe probably has nothing to do with ash.
Conclusion #3, mold material probably has nothing to do with ash.
Question #1, does FO have anything to do with ash?
Question #2, do temperature and humidity of the environment have anything to do with ash?
Question #3, does shape of the mold (or size) have anything to do with ash?
Supersoaper, since you claimed to be more scientific in soap making, can you please shine a bright light at this issue?!
