Astringency
also: dryness
A dry, puckering, sometimes harsh sensation in coffee, often a sign of over-extraction.
Astringency is a dry, puckering sensation in the mouth, like the feeling of strong black tea or an unripe banana. It is a mouthfeel, not a flavor, and it is usually unwelcome. The tongue and cheeks feel tightened and rough, and the finish turns scratchy.
Why it matters: astringency is one of the most common faults in home brewing, and learning to recognize it helps you fix a cup fast. It often arrives alongside harsh bitterness and a hollow, drying mouthfeel that drags down balance.
Where it comes from: the usual cause is over-extraction, pulling too much from the grounds, often because the grind is too fine, the water is too hot, or the brew ran too long. Channeling in espresso can also create localized over-extraction that tastes astringent. The fixes live in the four dials: grind coarser, shorten the brew, or lower the water temperature, then taste again to see if the dryness lifts.