Birch (Tar)

Birch tar is the dry distillation of birch bark, producing a thick, smoky, tarry oil that smells of campfire, leather, and a faint medicinal sweetness. It's the original 'Russian leather' base note — the material behind Cuir de Russie, Knize Ten, and the leather family's smokiest specimens. Birch tar is now heavily restricted by IFRA (it's a strong sensitizer), and modern leather compositions use it sparingly or substitute with synthetic isobutyl quinoline. Even at trace levels, it's instantly recognizable as 'leather.'