Geranium Oil, Réunion

#### Geranium Oil, Réunion. Also called **Geranium**** ****Bourbon**** **from the old name of the island of La Réunion (Ile de Bourbon), **Geranium Oil**, **Réunion **is the most important of all the geranium oils. It is produced in hundreds of small, mainly primitive stills which treat often less than one metric ton of plant material per charge. The daily output of oil from one still may be only a few kilos after many hours of work at two or more distillations, not to speak of scores of hours of back-breaking work in the field, ploughing, weeding, cleaning, fertilizing and cutting on steep hills where not even wheel-carts can go. The small lots of oil are sold to middlemen, who in turn sell larger lots to the brokers. The latter are usually French exporters or wholesale brokers. They bulk the oil lots, and this stepwise bulking of very small lots explains why the various drum lots of **Geranium Bourbon Oil **are fairly consistent and uniform in odor, but it also explains why the appearance of the oil is often poor: water, mud, precipitate and other worthless impurities may amount to several percent of the oil, and this can cause a sizeable loss for the buyer who wants to clean, filter or strain the oil. It is certainly no fun to buy water and dirt at the price of U.S. $ 55.— per kilo. It should be kept in mind, however, that certain exporters do filter the oil and remove the water before the oil is shipped overseas. The average temperature in Réunion island is about 25°C. At this temperature, the oil will dissolve more than one percent of water. Most of this water will "fall out" of the oil when the drums are shipped (particularly when air freighted!) to the buyer. The latter will find a significant amount of water at the bottom of his drum with the expensive oil. But in most cases. this water separation cannot be blamed upon the bulker or exporter in Réunion. The water must be accepted as a calculated risk. It can only be satisfactorily and finally removed after arrival at its destination. Freshly distilled **Geranium Bourbon**** ****Oil**** **has a very peculiar, rather obnoxious topnote which is partly due to dimethyl sulfide. The latter is probably not present as such in the leaves, but is produced during the rapid decaying of the plant material immediately prior to the field distillation. The unpleasant topnote will disappear after proper aeration or ageing of the oil, or when the oil is filtered or decanted. The color of the oil is then greenish-olive to almost brownish green. Later on, the green color fades, and the oil becomes more yellow when old. Its odor is very powerful: green, leafy-rosy, with a pronounced fruity-minty undertone and a rich, long-lasting, sweet-rosy dryout. As for the flavor of geranium oil, although the oil is very rarely used in flavors at all, it is worthwhile mentioning that it has a bitter taste, rather herbaceous and not at all pleasant as such. It is used sparingly in combination with rich and sweet flavor materials, e.g. in the classic "sen-sen" type of flavors: with ionones. artificial musks, vanillin, bergamot oil, patchouli oil, clove oil, heliotropine, etc. Old-fashioned toothpaste flavors still contain small amounts of geranium oil. In perfumery, this oil is used so commonly that it is hardly possible to point out its particular application. For certain purposes, it is preferable to use a so-called **Terpeneless Geranium Oil**** **(see monograph: **Geranium Oil, terpeneless**) which may be produced from geranium oil "Bourbon" or from any of the other geranium oils with various results. Most often, the deterpenation is merely a removal of the light fractions in a vacuum distillation, and perhaps a few percent of the tail fractions and residue. **Geranium Oil "Bourbon" **is frequently adulterated, although never directly on the island of La Réunion. Unfortunately, very few consumers receive their geranium oil in the original containers directly from the source of production, but the long transport and possible delay seems to scare many buyers. However, many lots of geranium oil are now air freighted not only to France, but also to more distant customers. The fluctuations in availability and cost of Réunion geranium oil has encouraged certain supply houses to cut or plainly adulterate the oil, and only a thorough olfactory examination, combined with a solid knowledge of the true oil, can protect the customer from these frauds. Instrumental analysis has been a great help in detecting plain adulterations, dilutions, cutting, etc. and there is probably no other essential oil which has been so thoroughly investigated, or upon which so much time and money has been spent in order to detect and identify "key" odor constituents, as the geranium oil. This highly sensitive type of analysis has, unfortunately, also developed the unethical "art of sophistication" (or plain adulteration) to a point where the evaluation of a geranium oil is a challenge to the buyer, to his perfumers' noses, and to the analytical instruments at his disposal.