The tannins are natural substances (they are present on the skin and in the seeds of the grapes) that are transferred to the red wines during maceration. We clearly find them when we feel a sensation of dryness and roughness in the front of the mouth, on the tongue and on the gums: this sensation is called “astringency”.
There are grapes that are particularly rich in tannins and which, if well managed, characterize the wine nicely: the best known example is probably Sagrantino, cultivated in Umbria, at the base of Montefalco Sagrantino DOCG.
Due to their property to dry out the mucous membranes of the mouth, tannic wines are very popular in combination with succulent foods, i.e. rich in liquids, such as a rare steak or braised meat.