Champagne is all about those bubbles. But as soon as you open a bottle, the carbon dioxide releases, and it's only a matter of time before the beverage loses its fizz. You can preserve the bubbles in the short-term, but you can't salvage them completely. Here are a few tricks to storing an opened bottle of Champagne to keep the bubbly as fresh as possible.
Use a hermetic stopper cork (an airtight cork) to seal the Champagne bottle immediately after you open it. These corks are available at most wine or party stores.
If you don't have a stopper cork, insert the long handle of a spoon into the top of the bottle.
Another option is to cover the top of the bottle with plastic wrap, and secure the plastic in place with a rubber band.