Definition - What does Tart mean?
Tart is a wine tasting term that typically describes the acidity present in the wine that the palate is keen to noticing. A tart taste in wine is usually sharp or sour and leaves a taste in the mouth that can be tangy and tingling. This is a common characteristic of wines with higher acidity levels that usually come from cool climate viticulture.
WineFrog explains Tart
When the total acidity of the wine is high, it is likely to have a tart finish in the mouth. These wines can have a tart taste because the fruit itself has a higher acid content or is unripe and can also occur if more acid is introduced through the blending process. For varieties that are naturally acidic, viticulturists have to take steps to make sure that the wine does not taste too tart or it will ruin the other flavors. However, in some lighter, white wines, a tart finish is desired and considered a good quality, especially if it lasts on the palate 15-20 seconds after swallowing.