Acid is one of wine's main ingredients. The different acids present in wine comprise what is known as the "acidity profile." They are:   Tartaric, Malic, Lactic, Acetic, & Citric
Acidity in wine will affect the taste of the food. Since both red and white wines that have too much acid often taste harsh and unpleasant, these should not be used in cooking. On the other hand, wines that do not have enough acid do not possess an interesting flavour and will not add much to a meal. It is best to find a well-balanced wine that will enhance rather than detract from the foods being prepared.
Most "cooking wines" do not have the correct level of acidity and tend to make meals too bland to truly enjoy. For this reason, always cook with wines that are actually considered "drinkable."