Carbonation in beer is a beautiful thing. It makes beer look like a living jewel as it bubbles to the surface. It makes the foam that caps a perfectly poured pint a billowy beauty the Germans call schöne Blume, a "beautiful flower."

 

Carbonation serves a great practical purpose: It puts a tingle on your tongue and cleanses your palate, making beer great with rich foods, cheeses and meats. And for you frat boys, it makes for some great belches.

 

Carbon dioxide gets into beer during fermentation. Yeast eats malt sugars and excretes alcohol and carbon dioxide (and some other stuff we’ll talk about later). In spirits and most wine, this just floats away, but in beer, it’s kept in and put to work, making beer great.

 

There are three ways to carbonate beer. You can add a little fresh unfermented beer to it in the aging tank and create a second carbonation, a process the Germans call kräusening (“KROY-zen-ing”). You can force pressurized carbon dioxide into the beer. Or you can use a champagne-like process and leave yeast in the bottle or cask to develop a natural carbonation.

 

Is one of these better than the other? Depends on what you like. Natural carbonation makes for a softer "mouth feel." Higher carbonation makes the beer more tingly and can create a higher perceived bitterness.

 

Once the beer gets in your glass, the bubble formation is actually incredibly complicated and not completely understood by physicists. If you’re really interested, try “Clouds in a Glass of Beer” by Craig Bohren for further reading.

 

Or ... just pour yourself another beer and watch the pretty bubbles.