Flavor

There are four basic flavors: sweet, sour, salty, and bitter. A fifth flavor - umami - is gaining acceptance and is described as savoriness produced from glutamates. Traditional belief was that each sense of flavor was perceived on a specific region of the tongue, but current belief is that each taste bud can sense all flavors. Tasters may perceive certain flavors stronger in different regions of the mouth though. Salty and sour tastes are the result of sensation from ion channels in the taste buds. Sweet, bitter, and umami are sensed through receptors known as G-protein coupled receptors. The flavors described to many foods, such as fruity in wine, are actually their aroma sensed retronasally as the food is eaten. Some textural sensations are often confused with flavors as well.

Grapes have a very large concentration of sugar compared to most fruits and sweetness is a very common wine flavor even though most of the sugar is consumed during fermentation. The large concentrations of acids in grapes produce sour flavors. Phenolic compounds from the skins and seeds can produce bitter tastes. Grapes possess little salt and this is an unusual flavor descriptor for wines. Umami is mostly associated with Asian foods cooked with MSG, but grapes do possess significant amounts of free glutamates and the sensation is often associated with many fermented foods. The flavor of a wine will be dictated by the concentrations of the different flavor producing compounds present in the wine.

Flavors will all interact with each other and can alter the perception of the sensation. The sour of acidity balances the very sweet sugar, which in turn masks the somewhat unpleasing character of bitter. Flavor sensations also can last over periods of time. Wines with lingering flavors are said to have a long finish, which also relates to aroma and textural sensations.