Birch Bark Oil

#### Birch Bark Oil. This essential oil is also known as **Oil of Sweet Birch, Cherry Birch, Southern Birch **or **Black**** ****Birch**. The tree grows wild all over the Southeastern United States up to Southern Canada. "Oil of Sweet Birch" is produced by steam distillation of the comminuted bark after it has been macerated (or, more correctly, digested) in lukewarm water for 12 hours. The essential oil is not present as such in the plant material. It is formed by enzymatic hydrolysis of the glycoside gaultherin. This process is similar to that of the formation of bitter almond oil. It is customary to distil wintergreen leaves (see **Wintergreen**** ****Oil**) or even **Teaberry Leaves**** **(so-called "Indian tea", possibly identical to wintergreen) with the birch bark. This is another example of botanical material from non-related species yielding almost identical essential oils. Strangely enough, the cost of harvesting wintergreen leaves is 5 to 8 times higher than the cost of collecting the birch bark. The oil yield from the wintergreen is somewhat higher than the yield from the bark, but insufficient to make it reasonable to add wintergreen leaves in the distillation. **Birch Bark Oil **is colorless or pale yellow, occasionally reddish tinted (from contact with iron). The oil smells so strikingly similar to methyl salicylate that it is hard to justify the existence of the essential oil. The flavor of wintergreen, "tea- berry" and birch bark oil was popular with the American Indians, and the early European settlers used wintergreen as a tea. Accordingly, it is not surprising that this flavor has become one of the most popular and typical American flavors. Its use in old-fashioned "Root Beer" beverages, later in all sorts of candies, chewing gum, toothpaste, etc., shows the well-established and lasting popularity of the methyl salicylate type of flavor in the U.S.A. Birch Bark Oil used to be one of the "big items" in American essential oil production (annual production was about 200 tons prior to World War I). The oil has almost completely lost its importance by now and it is merely a curiosity. What the trade offers today under the label of "**Oil**** ****of**** ****Sweet**** ****Birch**" may very well be a "touchedup" methyl salicylate from a chemical factory. **Birch**** ****Bark**** ****Oil**** **can boast one of the highest specific gravities of all essential oils known: 1.19 at 15°C.