Glycerin, or glycerol, is derived from plant-based oils. It also occurs naturally in fermented goods, such as beer, wine, and bread.
This ingredient was “accidentally” discovered in 1779 by a Swedish chemist heating up an olive oil mixture. He identified the resulting fat as glycerin.
Since the mid-nineteenth century, people have used glycerin to create soap. This process involves heating up certain plant oils and allowing the solution to cool and harden into bar form.