Rose Otto

#### Rose "Otto". The so-called "otto of rose" is the essential oil, steam distilled from the flowers of **Rosa**** ****Damascena**. In Bulgaria, water distillation is also carried out, but all stills are of comparatively modern design. The rose flowers are distilled quickly after harvesting, and the distillation demands considerable experience. It is common practise to redistil the distillation waters (cohobation process), and to bulk the oils from the two distillations. The yield of cohobation oil is several times higher than that from the first (direct) distillation of the flowering material. The phenylethyl alcohol in "Otto of rose" is derived almost exclusively from the cohobation water. It has been claimed that certain buyers were able to procure the first (direct) oil separately. The author has been unable to confirm this rumour. It has also been suggested that the rose flowers should be distilled not with plain water, but with water saturated with phenylethylalcohol (solubility about 1.6 percent in water at room temperature). This should result in the first (or "direct") oil being truly representative of the oil actually present in the flowers. The method remains in the research stage. The yield of oil would obviously increase significantly. The essential oil of **Rosa Damascena **is produced mainly in Bulgaria, but the U.S.S.R., Turkey (the Isparta region), Syria, India and China also produce this oil. The Turkish oil is steam distilled and is known as "**Anatolian Rose Oil**". Only Bulgaria and Turkey export quantities of any significance. The total world production is fluctuating between 1200 and 2500 kilos per year, equivalent to a value of between 2 and 5 million dollars (U.S.). Considering all products from the rose flower, and considering the fact that these products come from comparatively small areas of the world, the rose oils and extracts are among the most important of all natural perfume materials, and they represent a significant part of the agricultural economy for the countries in question (see tables in the last pages of this book). Bulgarian "otto of rose" is a pale yellow or slightly olive-yellow liquid which separates white or colorless blades of crystals (the so-called *stearopten) *at temperatures below 21°C. When further cooled, the oil may solidify to a translucent mass, the crystals growing from the surface due to their lower specific gravity. The odorless stearopten amounts to 16 to 22% of the rose oil. The liquid portion is known as the *elaeopten.* The odor of Bulgarian rose oil is warm, deep- floral, slightly spicy and immensely rich, truly reminiscent of red roses, often with nuances in the spicy and honeylike notes. The taste is slightly bitter at high concentration, biting-sharp, but becomes very pleasant in extreme dilutions. The suggested use level (for bouquetting effect in flavors) is about 0.02 to 0.05 mg%, and the **Minimum**** ****Perceptible**** **is 0.01 to 0.02 mg%. A well-known recent work on essential oils gives the value of 4.00 mg% (one part in 25,000) for minimum perceptible in *unsweetened** *water. The author believes that this incredibly high figure must refer to odor perception and not to flavor. But even so, the author observed a perceptible *odor** *of Bulgarian rose oil in water at concentrations below 0.05 mg%. A phenylethyl alcohol-free rose oil would obviously show much lower figures. Bulgarian rose oil is used so extensively that its high cost is almost the only limitation on its use in perfumery. Even traces, fractions of one percent of this oil in many types of perfume bases, can do wonders when correctly used. Carnation is one example of this. Rose oil blends well with many other florals, and jasmin is one of its most frequent companions. In flavor work, the oil is primarily used in tobacco flavoring and in a number of fruit flavors, e. g. apricot, peach, raspberry, strawberry, plum, etc., where traces of the oil impart a bouquet and a "rounding-off" effect, difficult to obtain with any other material. The wide popularity of the rose flower also greatly contributes to the fact that the oil can be used in trace amounts in unusual places where its presence will merely introduce a non-descript, but "familiar" and therefore pleasant undertone and naturalness. Obviously, this material has been exposed to adulteration ever since it first appeared on the market. The old-fashioned methods of adulteration have been slowly replaced by clever and artistic "sophistication", etc., but the experienced perfumer with the odor gamut of the genuine Bulgarian rose oil printed in his mind will rarely be fooled. However, additions of a few percent of ethylalcohol, diethyl phthalate, rhodinol from geranium oil, phenylethyl alcohol, etc. are often only detected by means of instrumental analysis. And even a few percent of solvent in a $ 2000-per- kilo-material is an adulteration of substantial economical interest for any "middle-man".