• The science of Champagne bubbles up again for New Year's Eve

    Francois Nascimbeni / AFP - Getty Images

    French researcher Gerard Liger-Belair works on a glass of champagne in his laboratory in Reims, located in the Champagne region in eastern France.

    By Alan Boyle, Science Editor, NBC News


    If you really want to impress your bubbly-sipping friends tonight, be sure to chill a big bottle of Champagne to somewhere between 39 and 50 degrees Fahrenheit (4 to 9 degrees Celsius), bring out the narrow glasses (not those wide plastic cups!) and pour the stuff gently down the angled side of the glass like beer.

    This is the scientific way to treat Champagne sparkling wine, based on research conducted over the years by Gerard Liger-Belair, a physicist at the University of Reims in France's Champagne region. His studies on the behavior of bubbly — including high-speed photography of popping bubbles and infrared imaging of carbon dioxide flow — have made him the world's highest-profile expert on Champagne science.

    It's a tough job — but somebody's gotta do it.

    "I love the beauties behind bubble science," Liger-Belair said in an email. "Since I became a scientist, many people have remarked that I seem to have landed the best job in all of physics, since my research on bubbles requires that I work in a lab stocked with top-notch Champagne — and I'd be inclined to agree."

    For Liger-Belair and his colleagues, it's mostly about the bubbles. To be sure, there's much more to sparkling wine than the sparkle: As many as 80 different vintages of wine may be blended together to create one batch of Champagne using the traditional process. A small amount of yeast and sugar is added, and the bottles are sealed up for fermentation. Months later, the yeast sediment is blown out through the bottle's neck — and then the bottle is quickly corked up and wired shut.

    Liger-Belair's research focuses on what happens next, when the cork is popped off. The CO2 that was created through the fermentation process bubbles out of the wine — tickling the nose with a fizzy aerosol of alcohol and flavorful ingredients known as volatile organic compounds. The more CO2 that can be liberated after the champagne is poured into the glass, the better.

    That's where science comes into play. Liger-Belair and his colleagues recently reported that larger bottles of Champagne retain more CO2 in the wine as it's being poured into the glasses. So if you have a choice between several small bottles and fewer big bottles, go for the big ones. But be sure those bottles are well-chilled: Warm champagne loses its CO2 quickly as it's being poured, leaving less to fizz up out of the glass.

    Ray Isle, executive wine editor of Food & Wine, shares five ways to get the most out of your New Year's bubbly.

    Speaking of the glass: Liger-Belair's team determined that tall, narrow-rimmed flutes produce a better effect than the wide-rimmed "coupes" that folks more typically associate with sparkling wine. That's because the CO2 rises out of a wide-rimmed glass too quickly, over a wider surface area. Also, glass flutes are better than plastic cups, and not just for aesthetic reasons: The plastic material is hydrophobic — that is, liquid-repellent — which means the bubbles are more likely to adhere to the sides of the cup and less likely to contribute to a nice fizz.

    If you really want to get your fizz on, wash your glasses before the party and dry them with a towel rather than letting them air-dry: The microscopic fibers of cellulose that are left inside the glass actually contribute to bubble production. Some glass-makers add tiny scratches to their Champagne glasses to create pleasing patterns of bubbles, and you can feel free to experiment with the same technique. (Just not with the expensive glassware.)

    When it comes to the pouring, don't splash the Champagne straight down into the bottom of the glass. Instead, trickle it down the side, like beer. That preserves more of the carbon dioxide for the bubbles that rise while you're drinking the wine. "The beer-like way of serving champagne much less impacts its dissolved CO2 concentration than the Champagne-like way of serving it, and especially at low Champagne temperatures (4 degrees C and 12 degrees C)," Liger-Belair reported.

    Liger-Belair has laid out many more findings about Champagne in a decade's worth of research papers — and in his book, "Uncorked: The Science of Champagne," which is being updated with the latest revelations for a new edition. One of his recent papers, an 88-page survey written for the European Physical Journal, is available for free download today.

    Here's a sampling of sparkling facts: 

    • There are six bottles' worth of gaseous CO2 packed into every bottle of Champagne.
    • A significant amount of that CO2 leaks out of the bottle through the cork. Liger-Belair's study of Champagne bottled in the 1990s suggested that almost a third of the CO2 could be lost over the course of 15 years. "Because the size of bubbles is linked with the level of dissolved CO2 in Champagne, bubbles get thinner over time when Champagne ages," Liger-Belair said.
    • The higher the wine's temperature, the bigger the "pop" when the cork is released. That's because the CO2 pressure increases with temperature. Some folks might keep their Champagne warm to maximize the pop, but be careful: A popped cork can travel as fast as 50 mph (80 kilometers per hour). Every year, the American Academy of Opthalmology warns that sparkling-wine corks rank among the top holiday-related eye hazards — and provides tips for proper cork removal.
    • Only 5 percent of the pop goes toward the cork's kinetic energy. Most of the rest goes toward generating the popping sound's shock wave. The pattern of CO2 that's set loose when the cork is popped is similar to the mushroom cloud created by an exploding atom bomb.
    • If you see a white wisp of mist rising from a just-popped bottle, that's not carbon dioxide. That's a fog of ethanol and water vapor, triggered by the sudden drop in gas temperature when the pressure is released. (That's what's known as adiabatic expansion.) 

    It might seem frivolous to devote so much attention to the physics of fizz, but Liger-Belair said his research is about much more than your single bottle of bubbly on New Year's Eve.

    "In fact, bubbles are a fantastic example of bubble dynamics in general, and studies dealing with champagne bubbles can be extended to many other areas where bubbles play a role, in natural as well as industrial processes. For example, marine aerosols created by bursting bubbles behave like champagne's bursting bubbles. ... The scales are different, but the basic principles are identical," he said in his email.

    Liger-Belair's research at the University of Reims is generally funded by enological and agricultural programs in France and Europe — such as L'Association Recherche Oenologique Champagne et Universit

    é, which was created to boost the Champagne region's best-known industr

    y.

    "As far as champagne is concerned, 350 million bottles sold per year all over the world deserve particular attention. The job may seem fun indeed, as any job made with passion should be," Liger-Belair said. "I am aware that devoting so much energy to studying champagne bubbles may seem 'weird,' but the implications of bubble dynamics are universal."

    So just before you take a sip of cool, sparkling beverage from your towel-dried flute, raise a toast to Liger-Belair ... and the science of champagne.

    Update for 12:45 p.m. ET: Legend has it that the wide-rimmed, bowl-like champagne coupe was modeled after the breast of Marie Antoinette (or the Empress Josephine, or Helen of Troy ...), but Snopes.com says there's no truth to the legend. 

    More about the science of alcoholic drinks:

    Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

  • Bubbly tastes best in a slim glass

    Univ. of Reims / PLoS ONE

    A false-color infrared image shows gaseous carbon dioxide escaping from a coupe glass of champagne after being poured.

    By Alan Boyle, Science Editor, NBC News




    Here's some science to celebrate on Valentine's Day: Researchers have shown why champagne tastes fizzier when it's drunk from a tall, narrow glass rather than a wide, shallow bowl.

    Wine aficionados generally prefer the narrow glasses known as flutes over the wide glasses known as coupes — but a study published this week in the open-access journal PLoS ONE provides a scientifically tested rationale. It's all about the bubbles.

    "Without bubbles, champagne would be unrecognizable, beers and sodas would be flat," researchers from France's University of Reims report. "However, the role of effervescence is suspected to go far beyond the solely aesthetical point of view. Recently, by use of ultrahigh resolution mass spectrometry, it was indeed demonstrated that ascending bubbles radiate a cloud of tiny champagne droplets overconcentrated with compounds known to be aromatic or the precursors of aromas."

    In short, the more bubbles you have, the more aroma you get from the bubbly. What's more, those carbon dioxide bubbles are the things that tickle your nose so enticingly.

    It only makes sense that having a glass with wider surface area at the top would disperse the escaping CO2 bubbles more widely than a narrow-mouthed flute, thus taking the bang out of the bubbly more quickly. To see experimentally whether that was the case, the researchers set up an experiment in which they poured good French champagne into flutes and coupes, and then watched what happened.

    The researchers used a micro gas chromatograph to track the levels of CO2 and evaporating alcohol in the "headspace" just above the surface of the liquid, where all the olfactory action is when you take a sip of champagne.

    "All along the first 15 minutes following pouring, concentrations of gaseous CO2 found close to the edge of the flute are approximately between two and three times higher than those reached above the coupe," the researchers reported.

    The findings confirmed the common-sense preference for flutes over coupes. Here's how the researchers put it in their paper: "Fluxes of gaseous CO2 per unit surface area offered to gas discharging are indeed significantly higher above the surface of the flute than above the surface of the coupe because the same total amount of dissolved CO2 ... has to be released by bubbles from a narrower surface, thus concentrating in turn more gaseous CO2 in the headspace above the flute."

    False-color infrared video shows carbon dioxide emanating from a champagne flute while the bubbly is being poured from a bottle stored at 64 degrees Fahrenheit.

    No surprise there. But the researchers were surprised to find that the temperature at which the champagne was served had little to no effect on the CO2 levels measured in the headspace. In retrospect, they surmised that factors such as CO2 density differences at the varying temperatures (53 and 68 degrees Fahrenheit, or 12 and 20 degrees Celsius).

    Sounds like somebody's going to have to do another experiment.

    This isn't the first time champagne has been poured in the name of science, and it probably won't be the last. The University of Reims research group is the same one responsible for earlier findings about the physics of fizz — such as the discovery that champagne retains its bubbles better if you pour the wine down the side of the glass, and the revelation that champagne poured into smooth-walled glasses holds onto its bubbles longer than wine in scratched glasses.

    It's no surprise that University of Reims is big on wine research when you consider that Reims is the largest city in France's Champagne region. And it wouldn't be surprising if some of the findings wind up in future editions of wine tasting guides. In a news release, study co-author Clara Cilindre suggested as much, saying that the results she and her colleagues came up with "might be a precious resource to depict [a] champagne consumer's sensation according to various tasting conditions."

    More scientific angles on alcohol:

    In additon to Cilindre, the authors of "Monitoring Gaseous CO2 and Ethanol Above Champagne Glasses: Flute Versus Coupe, and the Role of Temperature" include Gerard Liger-Belair, Marielle Bourget, Herve Pron and Guillaume Polidiri.

    Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.