Why does a raisin dropped in a glass of fresh champagne bounce up and down continuously from the bottom of the glass to the top?

According to the source I found, "A raisin dropped in a glass of fresh champagne will bounce up and down continually from the bottom of the glass to the top. This is because the carbonation in the drink gets pockets of air stuck in the wrinkles of the raisin, which is light enough to be raised by this air. When it reaches the surface of the champagne, the bubbles pop, and the raisin sinks back to the bottom, starting the cycle over."