Scooping a teaspoon into a bottle of bubbly isn't a proven way to keep the bubbles going. This is a widespread belief, but it has no scientific basis. The bubbles in sparkling wine are mainly due to the presence of carbon dioxide dissolved in the wine. When a bottle of sparkling wine is opened, the internal pressure is released and bubbles begin to form and rise to the top.
Slipping a teaspoon into the bottle does not prevent the carbon dioxide from being lost or the bubbles from degrading over time. To keep the bubbles in the sparkling wine, it is advisable to use an airtight closure cap or a vacuum pump to seal the bottle after opening it. This can help preserve the fizz for a longer period, but it's important to note that the bubbles will gradually decrease even with these methods. The best way to fully enjoy sparkling wine is to consume it within a few days of opening it.