Spearmint Oil

#### Spearmint Oil. The story of the spearmint is quite an amusing one. The plant—**Mentha**** ****Spicata**—originated in Europe, was introduced into the U.S.A., and is now one of the most important essential oil bearing plants of the U.S.A. The amusing part is that while it never was popular anywhere in Europe, the flavor of spearmint immediately became popular with the American public. Only recently, the oil seems to be appearing more and more and, as a modifier of peppermint flavor, it has been slowly regaining a foothold in Europe where peppermint always was the “only” acceptable flavor type for toothpaste, chewing gum, hard mint-candy, etc. There are still certain countries in Europe where it is virtually impossible to sell spearmint-flavored toothpaste or chewing gum. However, certain countries have used “mint” (**Mentha**** ****Viridis**** **and other wild spearmints) as a culinary herb in food and beverages for several hundred years (see below). Thus, we find the world’s main producing areas of spearmint in the midwestern U.S.A. (Indiana — Michigan — Wisconsin), and in the far-western states of Washington and Oregon. The midwestern American spearmint is still considered the best and, until recently, it also was the largest in quantity. In Europe, smaller quantities are produced in Hungary, Spain, Yugoslavia and Germany (almost abandoned), also in the U.S.S.R., India and, to an increasing degree, in China. Chinese spearmint oil is arriving in Europe at half the price of American spearmint, and it presents a serious threat to the American exports of the oil to Europe. All producing areas combined, the world production of spearmint oil exceeds 1000 metric tons per year. Due to a sudden increase in demand, the price of spearmint oil went up to twice the normal level during the spring of 1960. Furthermore, the plant is cultivated in many areas for use as a culinary herb, e.g. in Egypt (distillation abandoned in 1955) and in a number of European countries. In culinary terms, the word “mint” always refers to one of the spearmint varieties. The “na’na” of the Moslem countries is an almost non-hairy variety of spearmint, related to **Mentha**** ****Viridis***.** *It is cultivated in hundreds of thousands of small private gardens and used extensively as a tea (“shai”) mixed with Chinese tea as a tonic and popular infusion. At least three glasses of hot and heavily sweetened “shai” is a must for guests, travellers and friends at Moslem homes or camps all over the Mediterranean countries far into Sahara and in the Middle East. **Spearmint Oil **is produced by steam distillation of the flowering tops of the plants, which are partially dried prior to distillation. The distillation is carried out in the fields in fairly modern or very modern stills. The oil is sold as such, or it may be rectified according to the buyer’s specifications. The oil obtained right from the field stills is known as *natural *spearmint oil. It is a pale olive or pale yellow, mobile liquid with a very warm, slightly green-herbaceous odor, penetrating and powerful, truly reminiscent of the odor of the crushed herb. The flavor is equally warm, almost biting, spicy-herbaceous, somewhat bitter. Rectified oils are less bitter or not bitter at all, more burning-biting, and they have a much sweeter, balsamic taste in dilution. The suggested use level would generally be about 0.50 to 2.00 mg%, but the oil is actually used in toothpaste flavors up to a concentration of 300 mg%. There are children who “eat” toothpaste, and this fact must be kept in mind when the flavor materials are selected. The **Minimum Perceptible **for a good, rectified spearmint oil is about 0.10 to 0.20 mg%. In view of the penetrative odor, the flavor of this oil is surprisingly weak, a fact which is due to the water-solubility of carvone. **Spearmint Oil **is used primarily in flavors for toothpaste, chewing gum, candy, mouthwashes, etc. where it has attained great popularity as a modifier for peppermint (e.g. “doublemint”, etc.). In perfumery, the oil finds some use for its peculiar herbaceous-green effect in lavender fougère or even in jasmin compositions. The chief constituent of spearmint oil, **Carvone,**** **blends well with certain notes of the jasmin complex. The oil has a good and powerful effect in soap perfumes and is surprisingly stable in soap (carvone itself is a very delicate and unstable material). So-called terpeneless spearmint oil is often merely an isolated or a synthetic carvone. A synthetic **Carvone **has now been prepared on a very large commercial scale from d-limonene, a readily available monoterpene from the citrus oils. The d-**Carvone **(typical of caraway oil) as well as the l-**Carvone **(typical of spearmint oil) are both prepared from d-limonene. Even on the synthetic carvones, it is possible to distinguish by taste and odor between the dextro- and the laevo-rotatory form. The natural isolates of carvone from the two oils obviously have some “carry-over” taste and odor from the parent oil. In view of the above, it will be quite evident that adulteration of spearmint oil is not only possible but even a common occurrence. However, the Chinese spearmint oil is now on the market at such a low price that one cannot produce an artificial oil from synthetic carvone at a competitive price. Carvone was in 1960 sold at about half the cost of American spearmint oil (crop 1959 offered in the spring of 1960). If the cost of synthetic carvone drops further, there will again be an abundance of “artificial” spearmint oils on the market. A thorough flavor test should be included in any evaluation of spearmint oils prior to purchase. The American production of spearmint oil has steadily increased during the past ten years, and is still increasing with no significant drop in price (or demand).