Tannins

Tannins are polyphenolic compounds originally derived from the cell walls and vacuoles of sphagnum moss and other bog plants. In peat, they contribute to the acidic pH, brown coloration, and antimicrobial environment that preserves organic material.

Types in Peat

Both condensed tannins (proanthocyanidins) and hydrolyzable tannins are present. Condensed tannins predominate in sphagnum-derived peat. During decomposition, tannins are gradually incorporated into the humic substance matrix, so their free concentration decreases with increasing peat age and humification.

Cosmetic Relevance

Tannins provide astringent and antimicrobial effects in peat applications. The protein-precipitating action tightens pores and firms skin surface, relevant for face masks and toning products. Antimicrobial properties complement the broader antimicrobial activity of humic acids.