If I superfatted at 12%, a high olive oil soap: like 80% OO, 15% CO, 5% Castor would it still harden? Or, when superfatting this high do I have to have more solid butters, like shea in it? I've read that too much shea can be drying, is this true, or does this drying effect only occur on 100% shea butter soaps?
If you have enough lye to saponify the oils, it will harden. High OO soaps take longer to harden up though -even without a big discount. It will probably affect your bar's lather at 12%. But the best answer is to make a small batch and see what it does.