Hop Oil

#### Hop Oil. An essential oil is steam distilled or steam-and- water distilled from the **Hops **(see **Hop**** ****Absolute**). The oil has odor and flavor characteristics quite different from those of the absolute or the concrète from the same botanical material. **Hop Oil **is produced in Germany, France, and occasionally in other countries in Central Europe, in England, etc. The best oils obviously come from the areas where the hops are grown, since the volatile constituents of the hops are very sensitive to air exposure and oxidation. Resinification and the formation of free acids in particular will ruin the odor and flavor of hop oils, e. g. oils which have been distilled from old or dried material, or by improper storage of the hops or the oil. **Hop Oil **is a pale yellow (when fresh) to reddish- amber colored liquid, mobile when fresh, viscous when old. The odor of a *fresh** *hop oil is very rich, spicy-aromatic, sweet and heavy, but overall pleasant. Due to ageing or improper storage, the valeric, isovaleric and caprylic acids are formed and liberated, heavily influencing the odor and flavor to the disadvantage of the oil. Oils of sour, butyric-valeric or sweat-like odor should not be used at all. Cold stored in filled, well stoppered bottles, protected from daylight—or stored in solution, hop oil is fairly stable over a period of a year or more. Adulteration of hop oil is not uncommon. Nutmeg oil, copaiba oil, various terpenes and fractions from other essential oils, etc. have been identified in commercial lots of hop oil. The oil is used in flavor work for its rich, bitter- aromatic and somewhat spicy aroma. In spice blends, table sauces, tobacco flavors, and in flavors for alcoholic beverages, the oil may be used in combination with angelica root oil, cascarilla oil, and similar aromatic botanicals with which it introduces characteristic notes. The use of hop oil in the beer industry is comprehensively discussed in works dealing with beer brewing. The use level of hop oil in flavors is so strongly dependent upon the presence and concentration of other aromatic materials, that it serves no purpose to give approximate figures. The **Minimum**** ****Perceptible **of hop oil in neutral medium is about 0.03 to 0.06 mg% (fresh oil). In perfumes, **Hop**** ****Oil**** **lends a warm, rich and piquant, spicy note, useful in colognes, chypres, Oriental bases, fougères, etc. The true annual production of **Hop**** ****Oil **may be quite substantial, but the amount of oil available for the perfume industry is very limited. A few Hungarian and German distillers add sodium chloride to the distillation waters in order to produce a better separation of oil from the water. Furthermore, they may extract the water phase with benzene or other hydrocarbon solvents in order to collect certain water-soluble parts of the essential oil which are necessary to reproduce fully the volatile aroma of the hops. These "complete" Hop Oils are superior to ordinary hop oils in respect to flavor effect, but their keeping qualities are equally poor or even inferior to those of ordinary hop oils.