Bubbles are the hallmark of sparkling wines known as champagne. The size and behavior of the bubbles in the champagne glass are indicative of how the champagne got its fizz and therefore, are also a good indicator of the quality of the wine. While connoisseurs will appreciate a champagne that is fermented in the bottle (known as methode champenoise), vat-produced champagnes (known as charmat bulk) are a more cost-effective way to pop a cork and celebrate with a festive bubbly beverage.
Pour chilled champagne into a champagne flute. A flute works best for this test of quality instead of a saucer-type champagne glass.
Examine the size of the bubbles in the glass. Bubbles from a fine champagne whose effervescence is due to fermentation are pinpoint and very small. Bubbles from a lesser-quality wine are larger and reminiscent of soda bubbles, as they are a result of carbonation with carbon-dioxide.
Observe the activity of the bubbles in your champagne flute. Better champagnes form intricate trails of bubbles from the bottom or sides of the glass to the top. Lesser-quality champagnes form bubbles that tend to cling to the sides of the glass rather than forming trails.
A good way to check your research on champagne bubbles is to closely look at the label. Champagnes with fine trailing bubbles will bear the words "methode champenoise." This indicates the particular fermentation process that produces a better champagne.