Oakmoss Absolute

#### Oakmoss Absolute from Concrète. One of the most important of all the oakmoss products—if not *the *most important—is the **Absolute of Oakmoss**. It is generally prepared by alcohol extraction of the concrète (see monograph on **Oakmoss**** ****Concrète**). A special process involves the addition of solid paraffin or ceresin to the melted oakmoss concrète. The mixture is chilled, comminuted (by grinding or chopping) and subsequently extracted with ethyl alcohol. There are several types of oakmoss concrète, and the corresponding types of oakmoss absolute are produced from these types. Thus, the absolute from a benzene extracted concrète is still a solid or semi-solid mass, while the absolute from a petroleum ether concrète is liquid. The extraction of oakmoss directly with hot ethyl alcohol yields the so-called **Oakmoss Resin **(see monograph). **Oakmoss**** ****Absolute**** **is produced by the manufacturers of oakmoss concrète. The processing of oakmoss requires special equipment which cannot be used for anything else due to the extremely penetrating and tenacious odor, the resinous and insoluble coloring matter, etc. that is virtually impossible to remove from the extractors and stills. The absolute from benzene concrète is a dark green, semi-solid or solid mass (from hot-benzene extracted concrète) or a very viscous liquid or soft, plastic mass (from cold-benzene extracted concrète). White, needle-like or prismatic crystals may grow on the surface or on the inside walls of the container when it has been exposed to significant changes in temperature (sublimation of lichen acids). It is worth mentioning that these crystals are not a direct criterion of either a highly odorous product nor a very genuine one. But it has been established as a fact that these odorless acids contribute greatly to the stability of the highly odorous aldehydes (e.g. **Evernic Aldehyde). **Practically all of the odoriferous principles of oakmoss are chemicals of phenolic, acidic or aldehydic character. **Oakmoss**** ****Absolute**** **from petroleum ether concrète is a dark, brownish-green liquid, somewhat different in odor from the absolute of the benzene extraction product. It contains little or no chlorophyll, very few waxes or "resins". It represents one of the purest forms of extracted oakmoss, and is of the highest olfactory value. (See **Oakmoss**—uses of oakmoss products).