I have only been soaping a few months and trying several recipes to see what i like and what I don't like. Someone told me my soap would get rancid if not used in 6 months or so. Is this true? Is it only for soap with lard or tallow in it, or all soap? I was looking at Optiphen, since it is for oil based soaps. I have also heard about grapefruit seed oil, but heard it was not really a preservative. I have "The Soapmakers Companion" book and that's all she uses is grapefruit seed extract to preserve her soaps. Someone want to help me out? Please? and Thank you!!!!