Bubbles and Flow Patterns in Champagne
Is the fizz just for show, or does it add to the taste of sparkling wines?
Our work shows that the emission of aromas from a Champagne glass cannot be decoupled from what happens below the free surface, in particular the flow-mixing patterns. The classical engraved, slender and elongated Champagne glass mixes the whole domain of the liquid phase homogeneously, whereas in the engraved Champagne coupe, the recirculating flow region does not occupy the whole volume in the glass. Instead, a zone of no motion inhibits the formation of the desirable collar of foam at the glass edge.
We hope that our analysis of bubble-induced flow patterns and other objective elements of Champagne behavior will be just the beginning of the scientific study of the olfactory behavior of Champagne and sparkling wines in a glass. One area that merits further study is the release of aromas from bubbles. Droplets from bursting bubbles commonly contain much higher concentrations of aromatic compounds than those found in the bulk of the liquid. This is largely because bubbles attract surfactant molecules as they ascend, the same surfactants that can cause them to have increased drag. In Champagne these molecules include flavor-active volatile thiols, as well as other alcohols, aldehydes and organic acids.
Engraved glasses, particularly flutes, have much more vigorous mixing than non-engraved ones, so one would expect the etched glasses to release more CO2 bubbles and flavor compounds. But this may not be all good, because too many bubbles can irritate a taster’s nose, affecting the evaluation of the aroma that the winemaker is trying to achieve. We hope that there may be comparison testing of the same Champagnes from plain and etched glasses in the near future. The good news is that glassmakers are eager to experiment with various glass shapes, and engraving shapes and locations, in order to achieve the perfect glass of Champagne.
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