Soap Sweating & How to Fix It
Sweating is simply a phenomenon that happens between moisture and a humectant (the substance that preserves moisture), in this case, the humectant is glycerin. Glycerin in soap bases is a natural by-product of saponification and sometimes can be added as a moisturising agent. Humectants attract/absorb moisture from the air. Glycerin in soap attracts the moisture from the air which form on the surface of the soaps - this is so-called soap ‘sweating’.