Scratch and then sniff a black or yellow birch twig, and the pleasant aroma will likely put a smile on your face. What you are smelling is oil of wintergreen (methyl salicylate). This chemical compound is present in the inner bark in both species, although typically to a greater degree in black birch. In the trees, as well as several edible berries that grow in our region, the compound serves as a defense against herbivorous insects. Most people, however, enjoy the taste.
You can make a very nice wintergreen-flavored tea from peeled black or yellow birch twigs. I advise against trying to brew this the traditional way, though (i.e., steeping twigs in boiling water). The reason is that oil of wintergreen is volatile and easily driven off by heat, so if you attempt to make tea with hot water, your kitchen will smell great but there will likely be little if any flavor in your tea cup. » Continue Reading.