glycerol, glycerin, glycerine, or 1,2,3-propanetriol (prōˈpāntrĪˌŏl) [key], CH2OHCHOHCH2OH, colorless, odorless, sweet-tasting, syrupy liquid. Glycerol is a trihydric alcohol. It melts at 17.8°C, boils with decomposition at 290°C, and is miscible with water and ethanol. It is hygroscopic; i.e., it absorbs water from the air; this property makes it valuable as a moistener in cosmetics. Glycerol is present in the form of its esters (glycerides) in all animal and vegetable fats and oils. It is obtained commercially as a byproduct when fats and oils are hydrolyzed to yield fatty acids or their metal salts (soaps). Glycerol is also synthesized on a commercial scale from propylene (obtained by cracking petroleum), since supplies of natural glycerol are inadequate. Glycerol can also be obtained during the fermentation of sugars if sodium bisulfite is added with the yeast. Glycerol is widely used as a solvent; as a sweetener; in the manufacture of dynamite, cosmetics, liquid soaps, candy, liqueurs, inks, and lubricants; to keep fabrics pliable; as a component of antifreeze mixtures; as a source of nutrients for fermentation cultures in the production of antibiotics; and in medicine. It has many other uses as well.