Several varieties are known, but Siam and Sumatra Benzoins are the most important. The incisions are made when the tree is seven years old, and in Sumatra each tree yields about 3 lb. annually for ten or twelve years. A dark brown absolute is prepared from crude benzoin by extraction with solvents such as benzene and alcohol, followed by their subsequent removal.
The chief constituent of Siam Benzoin is benzoic acid (up to 38 per cent.), partly free and partly combined with benzoresinol and siaresinotannol; it also contains vanillin and an oily aromatic liquid. When quite pure it should be entirely soluble in alcohol and yield only traces of ash. Sumatra benzoin contains 18 per cent. or more of benzoic acid and about 20 per cent. of cinnamic acid the latter partly free and partly combined with benzoresinol and sumarisinotannol; it also contains 1 per cent. of vanillin, styrol, styracin, phenyl-prophyl cinnamate and benzaldehyde, all of which combine to produce its characteristic odour. Benzoin has a sweet, heavy aroma and blends well with sandalwood, rose, Jasmine, frankincense, myrrh, cypress, juniper, lemon and other spices.
Because of its antiseptic, astringent and expectorant properties benzoin has been used in vaporizer fluids for inhalation to relieve respiratory discomforts; and as an antiseptic and styptic on small cuts. The resinoid is extensively used as a fixative in perfumes, soaps, detergents, creams and lotions. It is classified as a natural flavor, used in most categories of foods, including alcoholic and nonalcoholic beverages, frozen dairy desserts, candy, baked goods, and gelatins and puddings.
Psychologically, benzoin has cheering, uplifting properties. It is helpful for grief, hysteria, panic and feeling rundown.
On the physiological level benzoin has expectorant, decongestant and mucolytic properties and has been used for respiratory infections, asthma, bronchitis, chills, coughs and laryngitis.
Contraindications:. Generally considered non-toxic and non-irritating however this oil can be a strong skin sensitizer so do not use on the skin.
Ernest Guenther, The Essential Oils, Krieger Publishing Company, 1952, reprint 1976
Leung and Foster, Encyclopedia of Common Natural Ingredients, John Wiley & Sons, 1996
Beverley Hawkins, Aromatherapy 201 Course 1999 revised 2000, 2001,2002, 2003, 2004
Mrs. M. Grieves, A Modern Herbal www.botanical.com