Definition - What does Acidity mean?
Acidity, in the context of wine, describes an element of the taste that a wine gives in the mouth. It refers to the fresh, tart or sour feeling created by the acids in the wine. High acidity makes a wine taste too sour or tart; low acidity makes the wine taste flat and flabby. This is why it is important for the winemaker to get the right level of acidity. They balance the three primary acids - tartaric, malic and citric - with sugar, alcohol and minerals as well as the other components of wine.
WineFrog explains Acidity
Acids play an important role in wine. The primary acids combine with fermentation acids (acetic, butyric, lactic and succinic) to preserve and stabilize the color of a wine. Higher acidity, such as in Sangiovese, means a crisp red in color; lower acidity, like in Syrah, means less stable blue pigments, so they appear muddier or brownish. In whites, low acidity causes the darker, brownish tones in a wine.
In general, acids add a sharpness to the flavor, detected by a prickling sensation on the sides of the mouth and tongue as well as a mouth-watering aftertaste. Too much acidity masks the wine’s flavors and texture, making the wine taste sour and sharp; too little acidity makes a flabby, flat wine with less defined flavors. Natural acids (tartaric, malic and citric) create fresh, pure tastes while fermentation acids (acetic, butyric, lactic and succinic) are milder and more complex.
The key to a great wine is (as always) balance - the winemaker’s task is to harvest the grapes at the right time and balance the acidity of a wine with sugar or alcohol. Acidity is highest in grape just before they ripen. As such, warm climates create wines with lower acidity levels, because ripening occurs quickly. Cooler climates create wines with higher acidity, due to the delay in ripening.
Acidity in a wine makes it a great partner for food. When pairing a wine’s acidity with food, remember that equal or more is the key. The wine must always be equal to or more acidic than the food you’re eating. If your dish is more acidic (like a sharp vinaigrette salad dressing) then the wine will taste flat and flabby.