Birch tar

Birch bark pitch made in a single pot: The birch bark is heated under airtight conditions, the final product consists of tar and the ashes of the bark.

Modern way of producing birch bark tar in a single pot: The birch bark is heated under airtight conditions, the final product consists of tar and the ashes of the bark.

Birch tar or birch pitch is a substance (liquid when heated) derived from the dry distillation of the bark of the birch tree.

Compounds

It is compounded of phenols such as guaiacol, cresol, xylenol and creosol.

Uses

Birch tar was used widely as an adhesive as early as the late Paleolithic or early Mesolithic era. It has also been used as a disinfectant, in leather dressing, and in medicine.

5,000-year-old chewing gum made from birch bark tar, with tooth imprints, has been found in Kierikki in Finland.^[1]

Ends of fletching of arrows were fastened with birch-tar and birch-tar-and-rawhide lashings were used to fix the blade of axes in the Mesolithic period.

Russia leather is a water-resistant leather, oiled with birch oil after tanning. This leather was a major export good from 17th and 18th century Russia, as the availability of birch oil limited its geographical production.^[2] The oil impregnation also deterred insect attack and gave a distinctive and pleasant aroma that was seen as a mark of quality in leather.

Birch tar is also one of the components of Vishnevsky liniment.^[3]

Birch tar oil is an effective repellent of gastropods.^[4] The repellent effect lasts about two weeks.^[4] The repellent effect of birch tar oil mixed with petroleum jelly applied to a fence lasts up to several months.^[4]

Birch tar oil is also used in perfumery as a base note to impart leather, tar, smoky, and wintergreen notes.

References

1. "Student dig unearths ancient gum, 2007.".
2. "Production of Russia Leather" (PDF). The Honourable Cordwainers' Company. 1807.
3. "Vishnevsky liniment and ichthammol: on the perspectives of application in military medicine and other fields". The BMJ. 12 June 1999. doi:10.1136/bmj.318.7198.1600. Retrieved 5 July 2016.
4. Lindqvist I., Lindqvist B., Tiilikkala K., Hagner M., Penttinen O.-P., Pasanen T. & Setälä H. (2010). "Birch tar oil is an effective mollusc repellent: field and laboratory experiments using Arianta arbustorum (Gastropoda: Helicidae) and Arion lusitanicus (Gastropoda: Arionidae)". Agricultural and Food Science 19(1): 1-12. doi:10.2137/145960610791015050.

External links

• Non-video demonstration