What is the best way to keep leftover wine?

The key is to limit the amount of oxygen the wine is exposed to and to reduce the temperature.  Following these inexpensive steps below can give you an additional 3 to 10 days on an open bottle of wine …

• Transfer the wine to a smaller (clean) container.  The 1/2″ of wine exposed to oxygen at the top of a 375 ml is substantially less than the 3 – 4″ exposed in a half full 750 ml bottle.
• Spray the leftover wine with inert gas that is heavier than air.  Inert gas will not react with the wine and will form a layer between the wine and the air we breathe.  Wine Preserve is a commonly used product.  Inert gases are usually a mix of: Nitrogen, Argon and/or CO2.
• Chemical reactions (such as oxidation) increase with temperature.  Lowering the temperature also lowers the speed of these chemical reactions.  So go ahead, stick that leftover red wine in the fridge.  When you are ready for another glass it will take about 30 minutes to come to room temperature.

The same elements in wine that allow it to age in the bottle will also help to keep the wine once it is open.  Wines with greater tannin, acidity and residual sugar will last the longest in the fridge.  Those wines that have delicate and highly aromatic aromas are more sensitive and volatile – they typically have the shortest life as a leftover.