It explains the chemical reaction known as saponification, where fat reacts with lye to produce soap and glycerin. Carl's homemade soap undergoes a week-long curing process before testing its ...

Hot process. In hot process soap-making, external heat accelerates saponification. Most soaps can be used the next day, though it’s ideal to wait 1 week if you want a harder bar. Cold process.

The lye reacts with the triglycerides of the fat in a process called saponification. When the proportions of fat and lye are correct, this exothermic (giving off heat) reaction completely ...