Once important in western herbal medicine, it is now used mainly as a fixative and base note in perfumery, the most widely used fixative for potpourri. Orris is also an ingredient in many brands of gin.
Fabienne Pavia, in her book L'univers des Parfums (1995, ed. Solar), states that in the manufacturing of perfumes using orris, the scent of the iris root differs from that of the flower. After preparation the scent is reminiscent of the smell of violets.
After an initial drying period, which can take five years or more depending on the use, the root is ground. For potpourri, this powder is used without further processing. For other uses, it is dissolved in water and then distilled. One ton of iris root produces two kilos of essential oil, also referred to as orris root butter, making it a highly-prized substance. Its fragrance has been described as tenaciously flowery, heavy and woody (paraphrasing Pavia, Dutch translation, page 40).
Typical iris perfumes (where orris prevails over the other components) are: "Orris Noir" by the London-based perfume house Ormonde Jayne Perfumery, "Infusion d'iris" (Prada*); "Tumulte" (Christian Lacroix*); "Aqua di Parma"* and "Iris nobile" (Aqua di Parma*); "Irisia"(Creed*); "Y" (Yves Saint Laurent*) and "Vol de nuit" (Guerlain*). "Orris Noir" contains regular orris root oil, not the oil of Iris nigricans, which is an endangered species.