Iron Age Fur Tanning – a Sustainable Practice

Tanning is among the most polluting industries in the world. Industrial-produced hides and skins are fully or pre-tanned with highly polluting chromium salts. The purpose of the study was to gain new knowledge about Iron Age tanning methods to clarify whether sustainable tanning methods can be developed based on this. Fur skin capes, uncovered in Jutland bogs, from Baunsø Mose (20-220 AD), Borremose I (365-116 BC), Huldremose I (1-174 AD) and Vindum Mose (386-203 BC) were analysed by Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Gas Chromatography-Mass Spectrometry (GC-MS) and morphological assessment of the skin fibres to identify tanning substances and material condition. Analyses were supplemented with source studies of previous visual assessment of the capes and measured shrinkage temperature of leather and skins excavated from bogs. Our results show that only the samples from Baunsø Mose, Borremose I and Huldremose I contain vegetable tannins. Furthermore, Baunsø Mose contains cow fat and Borremose I, Huldremose I and Vindum sheep fat. All contain indications of the presence of aluminum and iron compounds. The samples are decomposed to varying extents. Remnants from conservation were detected on Huldremose I, Baunsø Mose and Vindum Mose.