Booze School: Cask Conditioned Ale – Part 1

An Exploration of “Real” Ale: Part 1

A beer style I’ve long been passionate about is finally starting to catch on here in the Windy City. Next time you’re at the bar you might hear someone ask, “What’s on Cask?” To which you might ask yourself, “What the hell does that mean?”

Cask Conditioned Ale or “Real Ale” can be quite the fickle mistress. When properly executed, it’s quite the delicious experience, but serving a proper pint is a lot more complicated than you might expect.

What is Cask Ale?

So first off, what does Cask Conditioned Ale mean? When beer is in the fermentation stage, yeast consumes sugar and the byproducts are alcohol and carbon dioxide. In order to produce an end product with the proper amount of carbonation, the beer must undergo a secondary fermentation. However, in an effort to save time and provide a more stable and consistent product, most beer is force carbonated, think soda pop. When the beer is bottled or kegged, gas is pumped into the liquid in order to produce the desired amount of effervescence and head.

Cask Conditioned Ale on the other hand depends upon a secondary fermentation within the cask and as a result features natural carbonation. This type of beer served in a bottle is referred to as Bottle Conditioned Ale.

The end product is ale with a different kind of carbonation and mouth feel. The bubbles are smaller, more akin to champagne bubbles and the level of carbonation is considerably less than your standard brew. This results in a nice soft mouth feel. Furthermore, traditionally, cask conditioned ale is not pasteurized or filtered which many argue results in a richer, albeit more perishable, product.

How is it served?

Since Cask Conditioned Ale showcases a delicate natural carbonation, it has to be served differently. When you order a traditional draft beer, it’s pulled from the keg via the use of compressed gas. This gas can either be straight CO2 or a mix of CO2 and nitrogen. Beers like Guinness are pushed with a mix that’s mostly nitrogen, but we’ll leave that discussion for another time. When it comes to cask ale, bar owners have two options, they can either do a gravity pour or use a beer engine.

The beer engine, or hand pull / hand pump is something you may have seen at a bar but probably paid it little attention. They feature a large curvy tap handle and a big u shaped spigot. Using this method, the bartender pumps the handle a few times in order to make use of suction and pump the beer into the glass.


A gravity pour is the tried and true method of yesteryear. Think of jolly ole Friar Tuck. You place the barrel on a rack, pound in a spigot and pour away.

Huge proponent of the gravity pour

This method provides us with some classic etymology. If you sit a keg of Cask Conditioned Ale upright you are going to notice a few interesting features. First off, the barrel is a different size and shape than your typical American keg. What most Americans call a keg is actually a “half barrel”. On a side note, you can’t order a full barrel anymore. They are massive products of yesteryear which are impractically heavy. Cask Ale however comes in a barrel called a Firkin. Keg sizing and volume can get rather confusing, especially since measurements vary depending on country. To sum up: what most Americans call a “keg” holds 15.5 US gallons, while a firkin holds 10.8 US gallons

Behold the mighty firkin!

Note the little hole on the side. This is the bung hole. Once filled, the hole is plugged with a bung. When you tap the firkin, you insert a spigot into the top of the barrel and then rest the barrel on its side in a rack. You then drive a spile (little wooden spike) into the bung in order to break the seal of the firkin and allow for the beer to flow. You do this with a large wooden mallet; hence the phrase, tapping a keg.

A surly, drunkenly aggressive approach to a gravity pour

If one uses a beer engine, rather than placing a spigot in the top (side) of the firkin, you attach a keg coupler. A keg coupler is essentially a metal mouthpiece which is attached to a beer line that leads to the spigot of the beer engine.

Often times the types of beer served on cask are English Ales, as the whole process originated and has the greatest following in the UK. As a result some of the common styles that are offered in casks include: Bitters, Extra Special Bitters, Premium Bitters, Milds, Stouts, Porters, Brown Ales, etc. Many of these beers are lower in alcohol and as such you can enjoy a couple nice large Imperial or English pints without getting too schnockered. American brewers however will not be stymied by such conventions. Odds are you’ll encounter all sorts of beers available in a cask, including the ever popular India Pale Ale.

So now that we’ve established some of the basics, now let me explain why I’ve often times lambasted, “Ordering Cask Ale is a total crapshoot!”

To be continued shortly in An Exploration of Cask Ale Part 2

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