Tannic Acid Supplier — Leather Tanning & Technical Grade

What Is Tannic Acid?

Tannic Acid (CAS 1401-55-4) is a naturally derived polyphenolic compound belonging to the hydrolyzable tannin class. Commercially, it is extracted from gallnuts (Quercus infectoria), sumac leaves, or chestnut bark and is composed principally of pentagalloylglucose and related gallic acid esters. It has been used for centuries in leather tanning and is now employed across a wide range of industrial, food, and technical applications owing to its ability to bind proteins, precipitate metals, and act as an antioxidant.

Vegetable Leather Tanning

The classical and still widely practised use of tannic acid is in vegetable tanning of hides and skins. Tannins form stable cross-links with collagen fibers, converting raw hide into durable, firm leather used in soles, belts, saddlery, and traditional leather goods. Vegetable-tanned leather is valued for its biodegradability, natural feel, and aging characteristics. Tannic acid provides good tannage as a sole tanning agent or as a retan in combination with chrome tanning.

Corrosion Inhibition and Metal Treatment

Tannic acid reacts with iron oxide (rust) to form ferric tannate, a stable dark blue-black complex that passivates the metal surface and inhibits further corrosion. Commercial rust converters and corrosion-inhibiting primers leverage this reaction. Tannic acid is also used in metal surface pre-treatment before painting and as a corrosion inhibitor in cooling water systems and oil field applications.

Inkmaking, Pharmaceuticals, and Food

Iron gall ink — historically significant for manuscripts and documents — is produced by combining tannic acid with ferrous sulphate. Pharmaceutical and cosmetic applications exploit tannic acid’s astringent and antioxidant properties. In food production (E181), it is used as a fining agent in wine, beer, and fruit juice clarification, and as a flavor modifier in some applications.