Acta Scientiarum Polonorum
Silvarum Colendarum Ratio et Industria Lignaria

Tannins remain central to contemporary leather technology because they link biomass valorisation, collagen stabilisation, and circular sourcing. This article is intended as an expert opinion and a perspective contribution focused on the emerging challenges and opportunities in tannin extraction, characterisation, and sustainable leather tanning applications. The central argument advanced here is that extraction and tanning should be designed as a coupled system, since the composition of the extract strongly influences penetration, collagen interactions, and final leather performance. Current evidence shows that tanning behaviour varies not only with botanical source, but also with extraction conditions, molecular distribution, and the presence of non-tannin fractions that may modulate functionality [1]. Future progress will depend on selective green extraction, integrated analytical workflows, and process strategies that treat tannins as functional molecular systems rather than as generic plant extracts. This perspective identifies the principal research bottlenecks and outlines the most relevant priorities for predictive and sustainable vegetable tanning.