Birch

Smoky, tarry and phenolic, with woody, slightly leathery warmth and a dry campfire character.

• Pitch made from birch bark was already used by Neanderthals as an adhesive, for example to fix stone points to wooden shafts.

Among the odour-defining phenols in birch tar is guaiacol (C₇H₈O₂), formed when the bark is heated without oxygen; it smells smoky.