Keeping sparkling wine after opening

An opened sparkling wine loses pressure steadily, and with it the fine bead that is most of the point. A proper sprung champagne stopper — the kind that clamps under the lip — holds enough pressure to keep a bottle drinkable for one to three days in the fridge.

The teaspoon-in-the-neck trick does not work. It has been tested more than once and makes no measurable difference to retained carbonation; what does make a difference is the cold, which is why the myth survives — a bottle kept cold does stay fizzier, spoon or no spoon.

Cheaper sparkling wines usually go flat faster, because tank-method wines generally carry slightly less dissolved gas and less of the protein and mannoprotein that helps hold it.

A bottle that has gone flat is not spoiled. It is a slightly odd still wine, and it is perfectly good in a sauce or a sorbet.