Chances are good that you will pop a bottle (or two) of bubbly as you celebrate this holiday season. But have you ever pondered how those fizzy little bubbles get into your champagne or sparkling wine? More importantly, which glass is best for serving it? For answers to these questions we turn to Dan Souza, executive editor of Cook's Science at America's Test Kitchen.

THE SCIENCE OF BUBBLES

Have you ever wondered how the carbonation, the bubbles, actually gets inside your bottle of bubbly? There's interesting science to it. If you've ever noticed that air space at the top of a bottle of soda, beer, or champagne, it's actually really important. You're not being cheated by the producer, and they're leaving out some of the liquid. That air space is crucial to how much carbonation ends up in your drink. The pressure in that head space puts the CO2, that carbon dioxide, inside the beverage. That's what produces the bubbles.


Dan Souza

You know that wonderful pop you hear as you ease the cork out of the bottle? That is the sound of equilibrium being destroyed. When you have a closed bottle you have a closed system. It's in equilibrium, meaning the pressure in that air space above the liquid and the pressure in the liquid is the same. When you open up the cork, all the sudden you have way more carbon dioxide in the liquid than you do just in the air around it. The bubbles are going to come out of that liquid continuously until it reaches a new equilibrium. That new equilibrium is something we call “flat,” which no one likes in champagne or soda.

What’s really interesting is that temperature can have a big impact on how fast the gas leaves your beverage. You can see this if you open two bottles of champagne, one at room temperature and one that is really cold – out of a fridge or out of an ice bucket. With the one that's opened at room temperature, you're more likely to have the cork explode off and even some champagne to follow it. The cold one is more likely to stay in the bottle and be a quiet pop. The reason is that we know that gas expands when it heats up. You have all these tiny little bubbles in the champagne and the warmer it is, the more they expand and force the cork out.

BEST GLASSWARE FOR SERVING BUBBLY

Now we need to talk about glasses, which are important for champagne. There are two classic glasses to choose from: the slender flute and the wide, short coupe. It all comes down to surface area, the amount of air that will contact the wine. In a coupe, it's very wide; there's a lot of surface area. Whereas, in the flute, it's very small. The amount of surface area determines how fast the bubbles leave the drink because they only leave from the surface. In the coupe, it happens very rapidly, which is really nice. In the very beginning, you get a ton of that bubbliness in your nose and you can smell the wine nicely, but they're leaving the drink really fast. On the other hand, with the flute you get a little bit less coming right up at your nose, but it lasts a lot longer. That drink will stay bubbly from the time you start drinking it to the time you finish. That flute is the perfect glass for your champagne. There's something to think about when you're sipping your bubbly this holiday season.