The pearls are considered an important indication of the quality of a sparkling wine; the process of frothing / pearling is called moussing. The finer the rising pearls are and the more balanced the froth that forms on the surface (the pearl collerette, in French "la fine collerette de mousse à la surface"), the more delicate and sparkling the taste.
In the sensory test of a sparkling wine, the pearlability is also examined. This involves the nature of the pearls (fine to coarse) and the time for which the pearl lasts in the glass. The finer the pearls and the longer the play of rising bubbles lasts, the higher the quality of a sparkling wine is judged.
The band of rising pearls in the glass is called the "cordon". Essentially, the "quality" of the pearls depends on the way the sparkling wine is made. The longer the wine is stored on the yeast after bottle fermentation, the finer the pearls become. Large bubbles in sparkling wines, on the other hand, are pejoratively referred to as "oeil (yeux) de crapauds" (toad eyes). A normal bottle of champagne with a volume of 0.75 litres contains around 50 million pearls. With cheap mass products, the carbon dioxide is "blown in", but this only produces very large-volume pearls. A mousse point is useful for increased rising of the carbon dioxide bubbles in the glass. The fact that a silver spoon in the neck of the bottle prevents the bubbles from rising is a persistent but nevertheless false rumour. With still wines, a high proportion of carbonic acid is described as sparkling.