It's ********. The way to keep the fizz in sparkling wine is to make
sure it's well chilled before opening (chem 101, the colder it is, the
less gas that the liquid will give up) and treat it gently when
pouring, you want minimal sloshing inside the bottle.
Keep it in the coldest part of the fridge overnight and you'll have
plenty of bubbles the following afternoon or evening.