Bubbles are the hallmark of all sparkling wines, and they play a significant role in the cachet that surrounds this category. Even the terms “bubbles,” “mousse,” and “Champagne” elicit a pleasurable response in expert and novice consumers alike.
Though sparkling wine has been around for centuries—it first appeared in the early 16th century at the St. Hilaire Abbey in the Limoux region of Languedoc, France— its physicochemical properties properties have been studied only for the past two decades. At the Université de Reims Champagne-Ardenne, professor Gérard Liger-Belair’s group, Equipe Effervescence, Champagne et Applications, has compiled an overview of more than 20 years
of research.
From a sensory standpoint, sparkling wines are in a class by themselves. The olfactory experience is one of continuous change as bubbles ascend and burst, releasing both CO2 and volatile compounds in the headspace of the glass. Surprisingly, they activate the same pain receptors in the brain that are triggered by spicy food in what is known as the “carbonic bite.” As we take a sip, they excite our mechanoreceptors, creating a tingling sensation in our mouths.
Once the cork or crown cap on a bottle of sparkling wine has been popped, the key to maximizing the duration of the bubbles comes down to 1) how the wine is poured and 2) your choice of glassware. Infrared imaging has revealed that pouring sparkling wine down the side of a tilted glass (as you would for beer) is a gentler method that preserves more of the dissolved CO2 that creates or nucleates the bubbles.
Natural and Artificial Bubbles
Bubbles themselves are categorized as “natural” and “artificial.” Natural bubbles are those that originate directly from dissolved CO2, while artificial bubbles are produced by unseen forces like microscopic cloth fibers or tap water tartrates that get into the glass during cleaning or by laser-etched glassware; in the latter case, the intentional imperfections in the glass trap tiny pockets of ambient air and trigger CO2 bubble nucleation or effervescence.
Higher activity in the glass, whether from natural or artificial bubbles, is subjectively perceived to be associated with higher quality, so the technical evaluation of sparkling wine should be conducted in unetched glassware.
Along with their activity, bubbles are also evaluated for their size. CO2 bubbles in sparkling wine rise in a line in the form of characteristic “bubble trains,” and they grow larger as they ascend to the surface of the glass. In a narrow flute, bubbles will appear about three times larger than in a standard glass or coupe. Due to the
loss of CO2, older wines will have smaller bubbles (which are a well-known marker of older Champagne).
For the final say on glassware, gas chromatography reveals that you’re more apt to experience carbonic bite from a flute. Researchers agree that a tulip-shaped glass, shorter than a flute and narrowed at the top, delivers the optimal sensory experience. Either way, tasters are cautioned to pause before sniffing a freshly poured glass, allowing the liquid’s calmer flow patterns to reveal a truer sense of the wine’s aromas.
Many thanks, Deborah.
Kind regards from The Terroir of Peñalolén,
High Maipo Andean Wine Valley at Santiago de Chile, LRJ