Keeping Leftovers

The key to preserving the quality of leftover wine is to minimize chemical change. Lowering the wine’s temperature slows all chemical activity, and simple refrigeration works well for white wines, which usually keep well simply by being recorked and refrigerated. However, chilling causes dissolved substances in more complex red wines to precipitate into solid particles, and this causes irreversible changes in flavor. Leftover red wine is best handled by minimizing its exposure to flavor-altering oxygen, which can be done by means of inexpensive devices that pull the air out of a partly empty bottle, or by replacing the air with inert nitrogen gas, or by gently pouring a partial bottle into smaller bottles that can be filled all the way to the top—though the act of pouring itself introduces some air into the wine.