Tartaric acid is the primary acid found in grapes and is the most important acid in winemaking. It is responsible for the crispness, freshness, and balance of wine. Tartaric acid also plays a role in wine's color and stability.
 
Tartaric acid can be added to wine at any stage of the winemaking process to adjust acidity, enhance flavor, and improve mouthfeel. It is often used to acidify white wines, such as Chardonnay and Sauvignon Blanc, and to add balance to red wines, such as Merlot and Cabernet Sauvignon.