bitterness — having a harsh, disagreeably acrid taste, like that of aspirin, quinine, wormwood, or aloes.
acerbity — Acerbity is a kind of bitter, critical humour.
astringent — An astringent is a liquid that you put on your skin to make it less oily or to make cuts stop bleeding.
pungency — sharply affecting the organs of taste or smell, as if by a penetrating power; biting; acrid.
sourness — having an acid taste, resembling that of vinegar, lemon juice, etc.; tart.
tartness — sharp to the taste; sour or acid: Tart apples are best for pie. Synonyms: astringent, acrid, piquant. Antonyms: sweet, sugary, bland, mellow.
causticity — capable of burning, corroding, or destroying living tissue.