Thermal degradation study of vegetable tannins and vegetable tanned leathers

•Condensed tannins yielded higher amount of char than hydrolyzable tannins.•Tannins of higher reactivity produced thermally more stable leather.•Resorcinol and orcinol were identified as a marker of the condensed tannins in leather pyrolyzate.•Pyrolytic profiles can be used to differentiate between hydrolysable and condensed tannins.