Wintergreen oil

Oil of Wintergreen is an essential oil made of leaves from Gaultheria procumbens L., or at least its should be so. For years authoritative writers in the field of essential oils were complaining that the real wintergreen oil is not or hardly available.

S. Arctander (1961):
The once popular and well known essential oil of Wintergreen, also called Gaultheria oil, is about to become obsolete on the perfumer's and flavorist's shelf. More correctly, it has been replaced by synthetic Methyl Salicylate.

W. Poucher (1959):
The genuine oil is at present practically unobtainable, but an almost identical product, the oil distilled from the bark of Betula lenta, L., N.O. Betulaceae, is offered commercially as wintergreen oil.

Yes, quite old quotes. The reason for that is that very little good new literature on these aspects of fragrance materials is available. A more recent indication that something is rotten, is the (American) TSCA Definition (2008) of Wintergreen oil: Extractives and their physically modified derivatives. Gualtheria procumbens, Ericacenae or Betula lenta, Betulaceae.  

[Wikipedia (C): John Delano]

So either it is not made from the wintergreen plant, or it is synthetic. The real oil may be not available for over 50 years, unless of course the oil has made a revival. Nowadays even organic wintergreen oil is available, I really hope that checking of an oil is made of the right species is part of the organic certification procedure. So how rare is the real oil actually?

Meddling with wintergreen oil is rather simple: 90-99% of the oil is methyl salicylate, an easy to make ester, that is available in bulk for very low prices. Synthetic methyl salicylate might have a little methanol and salicylic acid in it (the two substances it is made of), but these might appear in the natural oil as well, due to hydrolysis. So how do you know it is the real oil?

The above makes clear what kind of problems smaller businesses and private persons have in determination of the quality of natural products:
- First of all you have to find out if there might be (still) some form of adulteration as a common practice.
- If that is the case: how would you know that your oil is the true oil?

To be continued...