4. What is the best way to preserve an opened bottle of wine? How long will it last?

The primary enemy of wine is oxygen (even though proper aging of wine requires it). Once wine is opened, it starts changing due to its interaction with the air. In some cases this is good (a wine "opening up" in flavor over the course of the meal, or even overnight in the case of some older reds), but it will always end badly if enough time elapses.

If you haven't finished a bottle and want to save it for later consumption, the best thing to do is to retard its reaction with oxygen. Putting it in the refrigerator slows down the reactions, so this is a good idea even for reds. (they should be warmed up again before serving). Just corked back up, whites could go for a day or three (depending on the kind and quality of the wine, the amount left in the bottle, and your own palate), reds might last a week that way.

There are several systems on the market to reduce the wine's exposure to oxygen.

One is a hand pump and rubber stopper arrangement which reduces the pressure in the bottle. They are marketed under various names, including Vac-U-Vin. Follow the directions and do not pump the wine down too much, or the volitiles will also evaporate, leaving a wine "dead". Proper use can extend the wine's life by a factor of two, allowing a red wine to be stored for two weeks in the refrigerator under some circumstances before it becomes less than interesting.

Another is a gas displacement system. Typically the gas is Nitrogen or Argon; it is introduced into the bottle, displacing the air that was there before, and then the bottle is resealed. [someone with experience here should finish this part of the answer.]

A third method is to rebottle the wine in a smaller bottle (such as a split whose bottle you saved), allowing very little air between the top and the cork. (that area is called the "ullage"). When inserting the cork, put the end of a paper clip, or a nail, or a wire, partially into the neck of the bottle as you insert the cork as a spacer, allowing air to escape (so that pressure doesn't build up). Then remove the object, allowing the cork to spring back. Tilt the bottle to wet the cork, but then store upright for some time (to give the cork a chance to fully spring back. Be sure to label the bottle! Some say that wine rebottled this way could be put back in the cellar and left there another year.

Jose
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