What is cold process soap? Cold process is the combination of water, fats and lye to make soap. It's called cold process because no heat is used in the making of this soap. Because it is done without heat, the soap has to cure meaning that the soap has to be allowed time for the lye to dissipate and leave the bar. This curing time varies depending upon what fats and oils were used to create that bar of soap.
Hot process soap can also be hand made. It also involves the combination of water, fats and lye. The only difference is that the mixture is slow cooked over heat until the Lye is cooked out of the mixture. Because the Lye is removed during the heating process, the curing time for hot process soap is only 24 to 48 hours unlike cold process soap which has a minimum curing time of two weeks. Some cold process soaps have to cure for two months!!!