It’s a very old adage – dangling a spoon (preferably silver) upside down in the neck of a bottle of Champagne or any other sparkling wine helps to maintain the fizz factor.
Many people swear by it, and apparently,the effect comes from the spoon making the air in the neck of the bottle colder, therefore denser. This area of denser air acts as a blanket, pushing down on the fizz, helping to keep all those bubbles in.
Does this really work?
In a word, no. If there is any effect, it’s negligible. The supposed layer of spoon-chilled air (which probably doesn’t exist) simply won’t exert anywhere near enough force to create the pressure needed to keep the carbon dioxide in solution. The fact that the gas is in solution under pressure is the reason why it bubbles up as soon as the pressure’s off (when the cork is popped).
What does actually work to keep leftover fizz, well, fizzy?
The only thing that will have any sort of effect in keeping the bubbles in leftover sparkling wine is to not allow it to get warm. Carbon dioxide, like other gases, is more soluble in liquids at cooler temperatures, so as soon as the wine starts to warm up, it’ll lose carbon dioxide.
This isn’t a miracle solution, though, as the CO2 will still escape over time and by 24 hours after opening, most of the fizz will be gone. You can also try hermetic corks, but again, they can’t exert enough pressure on the liquid inside the bottle.
You can always cook with it
If it’s good enough to drink at least halfway through the bottle, then it’s good enough to drink with. You might not have thought of using sparkling wine in a recipe, but it works surprisingly well in risottos and granitas. If you’re making a granita – a posh slushie, basically, you may have the ideal solution because the freezing process will preserve a lot of the CO2 and you won’t have to thaw it out and lose it.