Just Shove a Cork in It
Ok, you didn’t finish all the wine and you want to save the bottle for another day. What should you do? In an ideal world, you would move the wine to a container that was the “right size” for the amount of wine that you have remaining, cork it and store it in a cool place (like the refrigerator) until you wanted to imbibe. This will have the effect of slowing down the oxidation process via the cool temps and minimizing the wine’s exposure to oxygen. Oxygen is generally not going to be a friend to your wine and will reduce is fruitiness and character with time. It really is that simple. Remember that wine is alive and time is not your friend. Don’t wait too long before consuming as oxidation and other microbial actions may be taking place that will affect the taste of your wine.
What about all those neat products that vacuum the air out of the bottle? Well in fact we use them in our tasting rooms as they provide a nice closure for the bottle, but they don’t prevent the wine from being exposed to oxygen and nitrogen. They do reduce the amount of pressure the air has on the wine and hence will likely reduce absorption of gases, but I’m not sure if we could taste the difference versus a good cork or screw top.
You may then ask about the myriad of products that will put either Nitrogen or Argon gases in the ullage (space between liquid and top of container) thereby preserving the wine. The key here, in our opinion, is time is crucial for this make sense. You’ll want to get wine preserved within an hour or so of opening otherwise the top layer of the wine will be “saturated” with oxygen and the damage is done. Once, again we use this type of preservation method at Naked Winery when we are transporting or preparing wine for bottling and the amount of wine doesn’t completely fill our containers. We prefer Argon as the name "argon" is derived from the Greek word αργον meaning "lazy" or "the inactive one" (thank you Wikipedia), a reference to the fact that the element undergoes almost no chemical reactions. No chemical reaction is a good thing as we don’t want the wine to go bad. Also, Argon is much heavier than Nitrogen so we have a better chance of creating an Argon blanket on top of the wine when we’re gassing a container. The last bonus is Argon is about 1000 times less soluble than Nitrogen meaning is it less likely to be absorbed by the wine. Namely, that Nitrogen sparging pulls out Carbon Dioxide which means that your wine will not taste “fresh”.
Your best options are to either drink the wine or save it in a right sized container with a good closure at a cool temperature. Gassing is totally up to you and the amount of show you need to put on.