Glycerin for culinary use is a thick, clear, syrupy looking liquid used primarily in sweets to retain moisture and enhance sweetness. It is also used in candy making, such as fondant, to keep the candy from crystallizing. The ingredient may also be used in royal icing to keep it from getting hard.
Food grade glycerin can be either animal or vegetable based and can be used interchangeably, depending on the grade. The vegetable glycerin is typically made from coconut or palm oil while the animal derived counterpart is made from animal fats. It is most common to use vegetable glycerin in food preparation.