Describes one of the four basic tastes (along with sour, salty and sweet). Some grapes—notably Gewürztraminer and Muscat—often have a noticeable bitter edge to their flavors. Bitterness can also be imparted by the use of underripe or green stems during the fermentation and aging processes. If the bitter quality dominates the wine's flavor or aftertaste, it is considered a fault. In sweet wines a trace of bitterness may complement the flavors. In young red wines it can be a warning signal, as bitterness doesn't always dissipate with age. Normally, a fine, mature wine should not be bitter on the palate.