Cooking wine refers to inexpensive wine that has been treated with salt as a preservative. It is intended for use as an ingredient in food rather than as a beverage.
When a wine bottle is opened and the wine is exposed to oxygen, a fermentative process will transform the alcohol into acetic acid resulting in wine vinegar. The salt in cooking wine inhibits the growth of the acetic acid producing microorgasisms. This preservation is important because a bottle of cooking wine may be opened and used occasionally over a long period of time.
Cooking wines are convenient for cooks who use wine as an ingredient for cooking only rarely. However, they are not widely used by professional chefs, as they believe the added preservative significantly lowers the quality of the wine and resultantly the food made with that wine. Most professional chefs prefer to use inexpensive but drinkable wine for cooking, and this recommendation is given in many professional cooking textbooks as well as general cookbooks. Many chefs believe there is no excuse for using a low quality cooking wine for cooking when there are quality drinkable wines available at very low prices, such as two buck Chuck, which sells for $2 in California. Nevertheless, the sale of cooking wine persists both as a tradition, and because in some areas (such as New York State), cooking wines are manufactured with a low alcohol content (<5%) and can be sold in grocery stores, whereas ordinary wines with higher alcohol content (>5%) can only be sold in liquor stores .