Oakmoss Concrète

#### Oakmoss Concrète True Oakmoss Concrète is prepared by hydrocarbon solvent extraction of the lichen, **Evernia**** ****Prumastri*****, ***collected mainly from oaktrees in Yugoslavia, France, Italy, Corsica, Morocco, Hungary, and various central European countries. The lichen is often soaked in lukewarm water 24 hours prior to extraction. This operation is not absolutely necessary, but it does facilitate the extraction. However, it also changes the quality of the extract. The solvents used are: - petroleum ether (usually cold) - benzene (hot or cold) - gasoline (cold, but rarely used) - trichioroethylene (usually cold, used at all). A number of other solvents are used to produce "specialties" of the individual perfume supply houses. Ethyl ether, methylene dichloride, ethyl acetate, etc. are among the more rare solvents. Extraction may be performed at room temperature or in a boiling solvent under reflux. The extractors may be of the "stationary" type in which the solvent by gravity moves through the (stationary) moss, or it may be rotary type where the moss is rotated in the solvent. The most common method has been that of hot extraction with benzene, but during the past five or ten years petroleum ether extraction has become increasingly popular and is now undoubtedly the most important method. **Oakmoss Concrète **(hot benzene extracted) is a solid, waxy, dark green mass with a phenolicwoody, slightly tar-like but delicate and pleasant odor, reminiscent of seashore, forest, bark, wood, green foliage and tannery. Cold extracted concrètes are usually viscous or semi-liquid materials. A fair description of oakmoss concrète odor in general is hardly possible since there are so many different qualities, many of which have little or nothing in common with the odor of the botanical material, but most of which have very pleasant notes and pronounced "moss"-effects in perfumery. The dryout notes on a perfume blotter (moistened in a solution of the concrète), the overall odor type and the effect in perfumes, are the three most important virtues to study when an oakmoss concrète (or other extract of oakmoss) is selected. At sufficiently low concentration, **Oakmoss Concrète **can be used in soap perfumes, that is, if the color is no drawback. The concrète is not clearly soluble in alcohol, but it has very great fixative value and is of comparatively low cost due to the simple one-step processing. The bulk of all oakmoss concrètes, however, are used for further processing into absolutes, etc. (see these monographs). **Oakmoss**** ****Concrète**** **(petroleum ether extract) is a viscous, brownish-green liquid whose color is much less intense than that of the benzene concrète. Its odor is richer, more intense and diffusive than that of the benzene-extracted concrète. The yield of extract is somewhat smaller with petroleum ether than it is with benzene. Accordingly, the former is slightly more expensive. See also: **Oakmoss,**** **uses of oakmoss products.