Thanks to the magic of carbon dioxide, or CO2, in champagne and the rigid, wrinkled surface of the raisin, the tiny dehydrated grape will rise and fall in the glass, presenting it's own little dance show. The folds in a raisin allow for plenty of surface area for the carbonated bubbles to attach to which carry the raisin to the surface. When the carbon dioxide is released into the air, the raisin will gently sink the bottom awaiting the next ride.
But what about a bottle that's been sitting out all dinner? The carbon dioxide is quickly escaping, turning your bubbly into boring, alcoholic grape juice. Go ahead and drop a raisin in anyway. Give it a few minutes to work it's magic as the small amounts of gasses attach to the raisin and float to the surface, reigniting the carbonation for the perfect pour.
