Cod Oil and Birch Bark Tar. Like Legendary Russia Leather.
The finishing, in other words the process to which the tanned leather is then treated in a drum, produces a result which differs greatly to what is common today. To take the brittleness out of the 1.6–1.8-mm-thick leather and make it supple and durable, it has to be saturated with oil after tanning. Since the mid-19th century (without even mentioning modern processes), this has been taking place with animal tallow, known as “Dégras”. We go one step further back and use the substances to which experts claim legendary Russia leather owes its reputation: fish oil and wood tar. In a rotating drum, the leather acquires a long-lasting, and in time, perfect suppleness from the ancient fatting agents cod oil and birch bark tar. In the process, the birch bark tar naturally waterproofs the leather.