Beer Fact Friday: Cask Ale

Four Peaks Beer Engine

It’s time, friends, for another Beer Fact Friday. This week’s topic: cask ale.

Many Americans who vacation in England come back to the States complaining that all the beer they tried overseas was warm and flat. They’re not *completely* wrong: Most draft beer in England is served warmer and with less carbonation than the draft beer we’re used to. But there’s a reason for that: It’s cask ale.

Cask ale—or “real ale,” as the Brits prefer to call it—is different from the standard draft beer you’re familiar with in a number of ways. The most important difference is that while standard draft beer is fermented in large tanks and transferred to kegs for dispensing, cask ale is fermented and dispensed in the same vessel, which is called (surprise!) a cask.

Another point of difference: beer going into kegs is usually force-carbonated, meaning carbon dioxide is pumped into the beer before it’s packaged in order to get the level of bubbles inside to just the right amount. Cask ale gets 100 percent of its carbonation as a natural byproduct of yeast fermentation, and no additional CO2 is allowed to touch the beer before it gets to your glass.

That last requirement leads to a third major difference between cask ale and standard draft beer: While standard draft setups push beer in kegs to taps with carbon dioxide or nitrogen, cask ale is either served directly from the cask using a tap in its side and the force of gravity, or from a special device called a “beer engine” that draws beer from the cask through mechanical force. If you frequent breweries and beer bars, you’ve probably seen a beer engine at some point; if not, the second photo here displays the one we have at our 8th Street pub.

There are benefits and drawbacks to serving beer from a cask. Proponents of cask-conditioned beer claim there’s no purer expression of beer’s true flavor; the beer is literally living as it continues to ferment in the cask in your local pub, developing nuance with each passing hour. The downside is that because it must be exposed to oxygen in order to be dispensed, cask ale has an extremely short shelf-life—usually just two or three days.

True cask ale is somewhat scarce in the U.S., but there are a few breweries and bars that take the time to do it right. Here in Phoenix, SunUp Brewing Co. has an outstanding cask program, and we tap a new cask-conditioned beer—usually one of our existing beers infused with hops, spices or other fun ingredients—every Wednesday at 8th Street.

Got a topic you’d like to cover in a future #beerfactfriday? Let us know in the comments.