The production process of duffel is characterised by the immersion of the woven material in a bath of soap, urine or fuller's earth, which when heated and compressed causes the material to shrink by 10-30%, creating its compact quality. The process can be compared to that of loden in Austria.
The material became particularly popular from the late nineteenth century when it was used to make coats, especially for the British Royal navy, that could withstand the rain and cold.
Literature: Duffle Coat History, Details & Buying Guide, by Sven Raphael Schneider, Gentleman's Gazette, 3 January 2013.
WV, 22-01-2023