Tannins in wine have been described, particularly by novice drinkers, as having the effect of making wine difficult to drink compared to a wine with a lower level of tannins. Tannins can be described as leaving a dry and puckered feeling with a "furriness" in the mouth that can be compared to a stewed tea, which is also very tannic. This effect is particularly profound when drinking tannic wines without the benefit of food.

Tannins come primarily from the grape skins and the seeds and in biological terms are plant polyphenols that either bind and precipitate or shrink proteins.