One of the six taste sensations (in addition to fatty, salty, sour, sweet, umami), which is perceived extensively in the back part of the tongue (colloquially used in the context of a wine description is also hantig). The taste buds for bitter are many thousands of times more sensitive than those for sweet. This was particularly important in the primeval times of mankind, in order to be able to perceive poisonous substances, most of which also taste bitter, very quickly.
Bitterness should not be confused with the astringent effect mainly caused by tannins, but often occurs together with it. In wine, the tannin-like catechin is mainly responsible for the bitter effect. Bitter substances are present in larger quantities in aloe, artichokes, cinchona bark, hops, almonds, nut shells and orange peel. There are many alcoholic beverages flavoured with them, including bitter vino, chinato, wormwood and many others.
Bitter sensations develop slowly, but they remain in the mouth for a long time and are therefore noticeable in the finish. Bitterness can be almost completely masked by sweetness, while acidity increases its hardness. The sensation also depends on the wine temperature and is intensified at low temperatures. In the context of a wine-tasting, bitter is a rather negative description, but it does not necessarily mean a mistake. This occurs mainly with young red wines, but usually softens during ageing or bottle aging. For certain wines, such as wormwood, this is desirable. Bitterness can also be caused by insufficiently aged oak wood, unripe grapes or bitter rot. Improper or uncontrolled vinification can cause defects or the wine defects bitter almond (in the case of blue fermentation) and bitter tone (in the case of malolactic fermentation).