Choose Between Two Options

• C$30 for a craft-beer cruise at noon (C$54.54 value)
• C$30 for a craft-beer cruise at 5 p.m. (C$54.54 value)
• Sunday, September 13
• Includes commemorative mug and five tokens, which each can be redeemed for one 4-oz. beer sample from 15 participating breweries, including Big Rig, Double Trouble, and Junction
• Food is available for purchase onboard
• Cruise lasts three hours

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.