Introduction
Russia leather, known in Russian as юфть (yuft), is a unique type of bark-tanned cow leather that has gained recognition for its durability, flexibility, and water resistance. This distinctive leather undergoes a specific processing step after tanning, where birch oil is worked into its rear face. The introduction of birch oil not only enhances the leather’s physical properties but also provides protection against insect damage. Historically, Russia leather was a significant export commodity from Russia during the 17th and 18th centuries, prized for its quality and versatility in various applications. Its manufacture remained challenging to replicate outside Russia, making it an essential item of trade, particularly for the Muscovy Company. In German-speaking regions, this leather was referred to as Juchten or Juften.
Production Process of Russia Leather
The production of Russia leather involves three primary processes: tanning, oiling, and dyeing. Each step contributes to the final characteristics that set Russia leather apart from other types of leather.
Tanning
The tanning process utilized for Russia leather is similar to other vegetable tanning methods that employ tree bark. It involves soaking the hides in a solution derived from tanbark for several weeks, allowing the tannins to penetrate and preserve the leather effectively. The typical tanning process for Russia leather spans around five weeks, during which the hides are agitated twice daily and the tanning solution is refreshed weekly. A considerable amount of tanbark is required—approximately 2,880 liters for every 150 hides. In Russia, the tanbark is primarily sourced from the poplar willow (Salix arenaria) or, in Siberia, from birch tree bast. Spruce bark has also been noted as a viable alternative.
Oiling
The application of birch oil to the flesh side of the tanned hide marks a crucial distinction in producing Russia leather. This oil saturates the leather entirely while ensuring that it does not come into contact with the grain side to avoid discoloration and issues during dyeing. The use of birch oil not only contributes to the leather’s distinctive aroma but also significantly enhances its water resistance. Some reports suggest that seal oil may have been used alongside birch oil during this process. Ultimately, this stage can be viewed as a form of currying or curing rather than mere tanning.
Dyeing
Before dyeing takes place, the leather is softened using alum water and mechanically worked to achieve optimal flexibility. Traditionally, Russia leather was dyed red or black; while red dyeing was common and associated with an alkaline liquor derived from dye woods such as fernambuk (often identified as red sandalwood), black dye was produced less frequently and typically used for utilitarian purposes like horse harnesses. The black dye involved reactions between iron salts and residual tannins within the leather.
The Role of Birch Oil in Production
The production of birch oil, also known as ‘degot’, follows a specialized craft predominantly carried out by certain villages that supplied other sites engaged in leathermaking. The extraction process resembles partial pyrolysis combined with distillation—a method akin to that used for turpentine production.
To create birch oil, workers collect papery birch bark from older trees during late June when sap levels are highest. The bark is pressed flat under weights to prepare it for distillation, which occurs in large conical pits lined with clay. These pits are meticulously arranged with layers of birch bark over insulating materials like linden husks to control combustion effectively. A fire ignited at the center spreads gradually outward into the stacked bark layers over several days.
This labor-intensive process requires community involvement and can last up to ten days continuously, producing substantial quantities of tar suitable for use in leathermaking. While other regions may attempt to replicate Russia leather’s manufacturing techniques, producing authentic birch oil remains a challenge outside its traditional sources.
Historical Significance and Uses
Russia leather’s prominence surged during the 17th and 18th centuries as it became a sought-after export product due to its unique qualities and versatile applications.
Upholstery
One notable application of Russia leather was in upholstered furniture, particularly chairs that became popular during this period. Upholstering with expensive fabrics was common before this time; however, due to changing social norms emphasized by movements such as Puritanism during the English Civil War, simpler designs featuring plain leather were favored for their understated elegance. Chairs made with flexible Russia leather could endure significant wear over time without cracking—an advantage that inferior leathers could not match.
Footwear
Artykuł sporządzony na podstawie: Wikipedia (EN).