Vetiver Oil

#### Vetiver Oil. Although the essential oil of vetiver rootlets apparently is a product of comparatively recent times, the rootlets themselves have been used for their fragrance since antiquity. The parent plant is a grass, **Vetiveria**** ****Zizanoides**, a tall perennial which originates in India, probably also in Indonesia and Ceylon. The grass grows wild in India, Ceylon, Burma, the Malayan Peninsula, etc., but little essential oil is derived from the wild growing grass. For the purpose of distilling oil, the grass is cultivated in southern India, Indonesia (particularly in Java), the Malay states, Philippines, Japan, Réunion island, Angola (West Africa), the Belgian Congo, Haiti, the Dominican Republic, Brazil, Argentina, British Guiana, Jamaica, Mauritius, Martinique and, on an experimental scale, in many other tropical regions. The grass also serves as a soil protecting plant since its abundant lacework of rootlets will secure the soil on mountainous slopes against excessive erosion during the torrential tropical rains. Vetiver grass has been introduced in many volcanic islands and mountainous tropical countries as a soil protector. In India, several other grasses serve similar purposes, and some of them are simultaneously used for the distillation of perfume oil from the rootlets (see monographs on **Cyperus oils**). **Vetiver Oil **is steam distilled from cleaned and washed rootlets which are dried, cut and chopped, then again usually soaked in water prior to distillation. The distillation is undertaken near the place of harvesting with exception of small lots which are distilled in Europe or the U.S.A. from rootlets that have been imported from India, Indonesia or, very rarely, from Haiti. In the Belgian Congo, the distillation is centralized at one modern distillery in Kivu (eastern province). The cleaned rootlets arrive at this distillery from hundreds of kilometers away. The author has no reports of the distillation being abandoned during or after the July 1960 events in Belgian Congo. Réunion and Haiti are the largest producers of vetiver oil with India as a strong third. Most of the East Indian production is absorbed by this huge country’s local soap and perfume industry which is not saturated in any way by the 10 to 25 metric tons of vetiver oil annually produced in India (mainly in the northern India). Réunion produces 35 to 48 metric tons annually, while the Haitian production fluctuates (10 to 35 tons) according to the political situation. All other producing areas turn out less than 10 tons each annually. Indonesian production is increasing, and so is the Japanese. Belgian Congo oil is usually dark and may be slightly turbid, but of good quality (high alcohol content, and almost free from green-earthy, “potato-peel”-like top-notes). Angola oils come in two entirely different types: one is quite normal in odor and color, the other is very pale and attractive, grayish-amber colored and of dry-woody, almost cedrela-like odor, reminiscent of certain types of **Cyperus **oil. The pale Angola vetiver oil is distilled on a new plantation, and another oil, distilled in France from the same root material, has a similar odor and also the same peculiar laevo-rotation (hitherto found only in Indian vetiver oils) as well as very high alcohol + ester content. Thus, a general description of **Vetiver Oil **is not easy to give. The following suggestions for the use of vetiver oil apply to the “Bourbon type” (Réunion, Congo) and to the Haiti type of oil, totalling about 75% of the world production: **Vetiver Oil **is an amber colored to grayish brown, olive brown or dark brown viscous liquid whose odor is sweet and very heavy woody-earthy, reminiscent of roots and wet soil, with a rich undertone of “precious wood” notes. Oils distilled from too young rootlets and very freshly distilled oils may display some “green” potato-peel-like or asparagus-like topnotes. These are not appreciated by the perfumer, but the peculiar topnote is exploited in flavor work (see below). There is no definite rule to confirm the saying that dark oils are superior perfume oils, nor that the optical rotation will indicate the quality of the oil. The consumer who wishes to use his vetiver oil for isolation of vetiverol (a mixture of sesquiterpene alcohols in the oil) will soon find out during a test distillation how much vetiverol is in the oil. Vetiverol is responsible for the very faint, but tenacious, suave and sweet-woody odor, while the Vetiverone (corresponding ketone mixture) seems to lend bitter earthiness—and also tenacity—to the odor of the oil. Esters of vetiverol are still higher boiling and may have very little odor value, but they are excellent fixatives. Only the lower boiling “head fractions” are definitely undesirable from a perfumery point of view. If an oil has been improperly distilled, that is, if the distillation was “pushed” too far at insufficient steam pressure, the oil will usually have poor odor qualities. **Vetiver Oil **is used extensively in perfumery not only as a fixative, but also as an odor contributor in bases such as fougère, chypre, modern woody-aldehydic or ambre-aldehydic bases, Oriental bases, moss and wood notes, opopanax bases, rose bases, etc. It blends well with ionones, linalool, cinnamic alcohol, patchouli, sandalwood, oakmoss products, amylsalicylate, lavender, clary sage, mimosa, cassie, opopanax, isoeugenol, etc. The oil also serves for the isolation of **Vetiverol**** **and **Vetiverone**, the former again being used to produce **Vetiveryl**** ****Acetate**. This ester is also produced by direct acetylization of vetiver oil, but the method leads to a much inferior vetiveryl acetate since it is difficult to separate vetiverone and vetiveryl acetate by fractional distillation, and since vetiverone is affected by acetic anhydride in the process. Vetiverone is also used in perfumery. “**Vetiver**** ****Acetate**” is a commercial term for acetylated vetiver oil, more or less rectified. True vetiveryl acetate, also known under a number of brand names, is a very viscous, almost colorless liquid of faint, fresh-sweet, slightly woody odor, absolutely free from earthy, grassy, musty or fungus-like notes. This description unfortunately fits very few of the commercial products. Similar comments could be made for guaiacwood oil and guaiyl acetate, amyris oil and its “acetate”, etc. Haiti-, Réunion- and Congo vetiver oils are usually considered best for the isolation of **Vetiverol**. Indian and Angola oils often have a very high content of vetiveryl esters in their natural state. The “foreruns” (“heads” of distillation) from the vacuum distillation of vetiver oil can be used in flavor work. When extracted with weak alcohol or propylene glycol, the foreruns yield an “aroma” (see **Aroma**, Part One of this work) with a very striking resemblance to asparagus flavor. The taste is not very powerful, but resembles asparagus (or certain green peas) to such a degree that this soluble aroma may be used in food preserves (vegetables, etc.) to reinforce the flavor of asparagus. **Vetiver Oil **is occasionally adulterated with oils from roots of other grasses (see **Cyperus **oil), or it may be “cut back” with fractions from the isolation of vetiverol. After arrival in Europe or the U. S. A., Réunion oils may be cut with Haitian oil, Caryophyllene, Cedarwood derivatives, Amyris oil, etc. The annual world production of all vetiver oil types is about 90 to 130 metric tons. At least 20% of this quantity is tied up for “domestic purposes” in the countries of production (India, Brazil, etc.).