Choose Between Two Options
$25 for a meal for two or more ($39.96 value)
- One appetizer
- Two sandwiches
- Two beers or glasses of wine
$33 for a meal for four or more ($69.91 value)
- One appetizer
- Four sandwiches
- Four beers or glasses of wine
Carbonation: Beer’s Fifth Element
Whether black or tan, light or dark, ale or lager, just about all beer shares one trait: carbonation. Check out Groupon’s study of this natural process and toast beer’s bubbly side.
Scrutinize the contents of just about any bottle of beer and you’ll find it includes more than just hops, malted grain, water, and yeast. No matter how basic or old fashioned the brew, it’ll almost invariably be infused with something else, an elemental presence that is not necessarily part of the beer but that is nonetheless integral to its character: carbon dioxide. Carbon dioxide is a soluble gas, which means it becomes trapped in water—in this case, the water content of beer—under pressure. Releasing that pressure causes the CO2 to instantly revert to a gas, separating from the water molecules and rising in effervescent beads.
Carbon dioxide occurs naturally in beer—it’s created, along with alcohol, when yeast devours glucose (sugar) during fermentation. However, fermentation doesn’t usually take place in a pressurized environment, so much of the CO2 escapes along the way. To make up for this, brewers have two options: they can either try to trap the gas before the yeast has finished fermenting—as is done with cask-conditioned ales—or, using modern machinery, inject CO2 directly into the liquid afterward (much like artificially carbonating soda or seltzer). Although artificial carbonation has become the industry standard in America, many European brewers (and beer drinkers) prefer the natural approach, which is sometimes associated with a less fizzy mouthfeel.