We've purchased small quantities of different essential and fragrance oils over the years. I was going through the boxes during the snow storm re-smelling different oils. I kept going back to a bottle of Birch essential oil.
Birch essential oil, Betula lenta. The method of extraction is steam distillation from the bark and the country of origin is Canada. Jerry thinks it's very similar to Wintergreen but more complex. I made a single batch, 16 bars and am making them available.