Tannins are natural phenolic compounds found in grape skins, seeds and stems, as well as in the wood of barrels. They are divided into condensed tannins, which come directly from the grape, and hydrolysable tannins, which come from the wood (such as oak) used in ageing. In wine, especially red wines, tannins provide structure, body and ageing potential, acting as natural antioxidants. They also generate a sensation of astringency or dryness in the mouth by binding to proteins in saliva, influence colour stability and fixation by interacting with pigments, and contribute to aromatic complexity with notes of vanilla, cocoa or spices. Over time, tannins soften, resulting in more rounded, balanced and long-lived wines.

BioSystems offers automatic analysers and enzymatic or colorimetric kits designed to quantify total tannins and other phenolic compounds in musts and wines. This equipment uses UV-Vis spectrophotometry, which measures light absorption at specific wavelengths associated with tannins. This provides an objective, accurate and reproducible measurement of tannin content, allowing the winemaker to control its extraction during maceration, its evolution during ageing and its influence on the stability and final quality of the wine.

In the following document, you will learn what tannins are, the most commonly used methods, and their differences:

Determination of tannins in wine by spectrophotometric analysis