In general, red wines start to lose their aromas and flavors and begin to taste acidic 2 or 3 days after opening. However, the more bodied a wine is, the more likely it is to have a higher tannin-content. Tannins reduce a wine's deterioration upon contact with oxygen and since lighter red wines have fewer of these antioxidant compounds, they tend to deteriorate faster.
Red wines that are prone to rapid deterioration include Pinot Noir, older vintages, wines without sulfites, organic wines and wines that are light in color, such as Grenache and Sangiovese.
To extend the shelf life of an open bottle of red wine, it is recommended to replace the cork after each pour. It should also be stored in a cool, dark environment. Storage in a refrigerator will help to preserve the wine, but it should be cooled gradually first. To return the red wine to an appropriate temperature for drinking, it should be submerged in lukewarm water. Sudden changes in temperature are likely to contribute a wine's deterioration.
Since contact with oxygen is largely responsible for a wine's spoilage after opening, it is also recommended to store bottles upright. This reduces the surface area of the wine subject to direct contact with oxygen. Specially-designed vacuum pumps can also help to reduce oxygenation.