Definition - What does Drying Out mean?
"Drying out" is a term used in wine tasting when the wine is out of balance, usually, it refers specifically to when the fruit nuances of the wine are fading. Thus, the other elements of the wine which make up its body are more dominant, like the acidity, tannin or alcohol.
WineFrog explains Drying Out
If a wine is "drying out", or has already dried out, the taster will not notice much fruit characteristics, but they will find that either the acidity is too harsh, the tannin is to harsh or present or the alcohol is too strong. Wines in this state can never be fixed or improved with further aging in the bottle or decanting. Proper storage in an area with 65 to 70% humidity may prevent a wine from obtaining this characteristic.