What’s a Cask Ale?

Our local microbrewery in Houston, St. Arnold’s, has a series they are doing where they take a tried-and-true beer recipe and change the yeast. When I got to my local pub to try a side-by-side comparison, we were presented with two options – whether or not to have it on tap or via the cask.  Perhaps you’ve seen these at a bar or witnessed a bartender hand pumping what looks like a chocolate syrup dispenser. Just for you, I tried both versions and here’s what I have to report about Cask Ales.


The cask version of the beer was cloudy in appearance. That’s because the cask version of a beer is unfiltered. Yes, Dr. Frankenstein, it’s alive. It also came out appearing a bit flat. Cask ales are not served by pumping additional nitrogen or CO2 into the keg. The pressure that builds up in a keg by pumping gas into it is used as a handy delivery system to push the beer from the keg into a tube and out the tap. This creates a familiar fizzy drink. A cask ale is delivered via a vacuum of sheer elbow grease. To pour one is a bit like arm wrestling.  

While it doesn’t affect the color, it does change the appearance and as I’ve used the head of a beer to indicate freshness before, I think it’s only fair to say that in the case of a cask, the fresher the beer, the flatter the head. That doesn’t mean it’s still not naturally carbonated. A cask ale is not comparable to a flat soft drink. With a cask ale, it’s more like the difference between the carbonation you experience from a bottled beer versus a canned soda. It’s still there; it’s just not one of the main characteristics of the beer.

Cask ales are brewed in limited quantities because they aren’t pasteurized, so they are conditioned inside the container they are dispensed out of and then served fresh from the brewer. What’s conditioning? That’s the secondary fermentation process. See more about this in the Brewing section.


Cask ales in the US are conditioned, unpasteurized and unfiltered. We covered unfiltered in the Color section, so let’s talk about what it means to be conditioned. Conditioning is also know as secondary fermentation and it relies on the power of suspended yeast. During the brewing process, most of the yeast used to ferment the beer sank to the bottom after it gorged itself to death on all that tasty sugar, but the strongest ones survived and are still happily eating away and burping up (we’ll go with that end) gas after being bottled or put into a cask for transportation. Like feeding your goldfish before you go away for the weekend, some brewers add a bit more sugar to the solution before closing it up to give the little buggers a reason to live until they reach your glass. Not all beers are conditioned, so this is one of the reasons why casks are special. Another reason is that they are delivered to their final destination a few days before tapping and serving. This gives the yeast time to work its delicious magic and then settle back down to the bottom. The beer is still not crystal clear but it is clarified (more on this under Quick Trivia). 

So, like decanting red wine, a cask ale needs to sit a spell before it’s ready to be served. During this time, the cask has to be vented to prevent it from exploding behind the bar. All that carbon dioxide has to go somewhere. Some of the darker ales can be aged for months in the cask, but once tapped, the clock starts ticking. With all this babysitting and the need to serve the entire cask in a matter of days before you have to throw it out, you can see how having a cask ale sets your local icehouse apart from what are commonly referred to as brewpubs. If they aren’t already brewing their own beer to serve in the restaurant, then places that go to the trouble of tending to a cask are also going to carry seasonal brews and probably a few Belgian bottles. That’s where I want to be when the zombies invade. And now for a lesson in pasteurization.

For Home Brewers

Cask ales are perfect for home brewers. Without the need to pasteurize, it makes the brewing process less complex. Pasteurization is the process of heating a foodstuff up and then quickly cooling it down, thereby killing any bacteria and in our case, yeast. This preserves the shelf life, but if you’re brewing at home, your intent is probably not to keep beer around indefinitely. Alcohol content and hops are all we need to preserve a beer but I should tell our novice brewers not to underestimate the importance of sterilizing all your equipment. Nothing ruins a batch of beer faster than e. Coli, so wash your hands.

Other than a tip I found to skim the yeast off the top a couple days into the primary fermentation, there’s nothing different about the brewing process of a real ale (another term for cask ales), only in the storage and delivery mechanism. Conditioning in the bottle is still considered a cask ale. The waiting is the hardest part as you may find that it takes up to 45 days for your cask conditioned bottled beer to mature. But time is not on your side. Your beer is still unpasteurized, so it’s not going to get better the longer you let it sit. Keep on eye on the sediment. Don’t drink it until it’s developed a layer at the bottom and I hope I don’t have to tell you not to drink the layer that forms.  

Alcohol Content

This depends on the style of beer in the cask. They typically rate between 5.5% and 6.5% ABV. Watch out for seasonal casks as they tend to tip the scales past 7% and on up to 8%. Knowing the ABV is a good way to know how much you’ve really had to drink. Two beers is equivalent to one glass of wine.


These are typically referred to as Real Ales in the UK but the term cask ale only refers to the fact that no additional gas is pumped into the beer. In the US, we use the term to indicate that not only is it served from the container where secondary fermentation took place but that it is unfiltered and unpasteurized.

Quick Trivia

Finings are added to the beer to clarify it. You might not want to know that it’s the stuff found in the swim bladders of tropical fish. May I suggest a food pairing with haggis? That means that cask ales are typically a no go for vegetarians. Diehards will want to do some research into whether or not an animal-based fining such as gelatin was used in the making of your libation. Barnivore is a website that monitors vegan-friendly beers and wines. Veggie Wines does the same thing in the UK.


These are going to vary from brewer to brewer. All I can say is that if you find yourself in a place with a cask ale, order one for the cause.

  • Cask Nights every Thursday at Karl Strauss’ in Southern California. Since this is my second time to promote this brewer on this blog, I want to make it clear that I am in no way affiliated with this establishment. I just like ’em.
  • Year-round casks at Wynkoop in Denver.
  • The Malted Barley Appreciation Society‘s list of pubs in New York serving cask ales.
  • Cask Ale Festival in Atlanta on March 5, 2011.
  • Cask Ale Week in the UK at the end of March and into April.
  • CAMRA list of festivals and events. Not all of them cask-related but a great resource for US travelers looking for a reason to take a vacation in the UK.

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