Bitterness

Bitterness refers to one of the fundamental tastes perceived toward the back of the tongue, linked in wine to certain phenolic compounds and tannins. Distinct from astringency, which is a tactile sensation, it is a gustatory perception that, in measured amounts, lends structure and length. In excess it often signals green stems, over-extraction or poorly integrated oak, and lingers unpleasantly on the finish by hardening the wine's closing impression.