2018, Seattle. Cask Beer Fest. It’s coming up. You’re asking yourself right now, almost too late to really find out: what is a cask beer? I got excitable and dropped $40 on a ticket but now I have no idea what I got myself into. Well, guess what, just in the nick of time, the Cycling Cicerone will ride in to save you with another beer snob lecture. Welcome to the exciting and wonderful world of Cask Beer!
Before I get started, I want to mention that I will be at the Cask Beer Fest this Saturday during the evening session with my mic in hand, taking Washington Beer Talk to the streets to find out what people know and want to know and talking to brewers about cask beer. If you want to be in an episode of the Washington Beer Talk podcast, then seek me out on Saturday!
So what makes a cask beer? Here’s the nickel answer: it’s a beer that is served slightly warmer and less carbonated than a normal beer. It’s carbonated naturally via yeast and traditionally was “refrigerated” naturally as well via a slightly cool hole in the ground, aka cellar. These two differences have a major impact on the mouthfeel of the beer and will totally change a beer’s flavor without changing any of the ingredients. It’s basically making and serving a beer that is deliberately slightly warm and slightly flat. There you go, for a nickel, you now know everything that you need to know about cask beer in time for the festival. For a dollar more, here comes the good nerd stuff.
Cask beers are self-carbonated. This is essentially the way beer was made and served since the dawn of beer. Up until the invention of modern carbonation methods, there was no other way to do it. These days, when a brewer wants a carbonated beer, the easiest and cheapest way to do that is to physically inject co2 from a tank straight into the beer. This lets you control very precisely the amount of carbonation in your beer. Before this was possible, the yeast did all the carbonating themselves as part of the fermentation process. Most of it escapes the beer and goes into the air, but if you seal off the fermentor, then the co2 dissolves back into the beer creating carbonation. But why is it served so warm? In the days before refrigeration, the easiest and cheapest way to keep beer cool was to keep in in the cellar where the insulating earth around it kept it as cold as possible, ideally around 50-55 degrees F, also known as “cellar temperature” (they really blew a fuse when they came up with that name, right?). It is notably warmer than the 34-38 degrees F you are used to in the beer you normally drink. Refrigeration keeps the beer cold enough to prevent spoilage and allows more co2 to remain dissolved in the beer (remember that from chemistry class?). We like refrigeration now, but back then people made do with what they had.
Here in the US, we didn’t exist all the long before modern beer technology came around, so when it did, we gave up the traditional ways quicker than you could write a research paper on them. Who needs a beer that is traditional when you can pasteurize it, throw it on a refrigerated train, and ship it from Milwaukee to LA. We wanted beer that was cold, refreshing, and above all, extremely consistent, so goodbye to all that. This message brought to you by Pabst Blue Ribbon. These days, in response to the mass market homogenization of beer of the 60s and 70s, the Campaign for Real Ale (CAMRA) in England fights tirelessly to keep the traditional ways alive. Keeping Cask beer, or Real Ale as they call it, alive and traditional is their primary mission.
In order to count as a cask beer, the beer needs to have undergone a secondary fermentation in the cask. That is, not quite finished beer is moved to a special keg, called a cask, where the last little bit of fermentation produces enough co2 to lightly carbonate the beer. It is then served directly from the cask. This is a risky process since yeast tend to do whatever it is they damn well please when left to their own devices inside a cask, so rather than letting the cask over pressurize and potentially explode in a much-less-fun than-it-sounds flood of beer, casks are built in such a way as to let off excess co2 as the fermentation completes. This is done via a “spile” which is basically a poor man’s airlock made of porous reed that allows co2 to slowly vent out without letting much of anything back in. When the secondary fermentation has reached the sweet spot, determined via a very scientific approach called guessing and hoping, the spile is replaced with a more airtight “hard spile” which seals any new co2 in to create the right amount of carbonation.
When it comes time to serve, a tap is driven with a mallet through the side of the cask and the beer is poured via gravity. No co2 is used in serving as with modern draft beers which use pressurized tanks of co2 to force beer out of the keg and down the draft lines. If a cask can’t be on the same level as the serving bar thus allowing gravity to serve the beer, then a vacuum pump is used. You may have seen these steampunk looking tap handles around. Much like a bike pump, pulling the lever sucks beer in to be dispensed. Using co2 to push beer prevents exposure to oxygen which will spoil a beer in fairly short order. Since co2 dispensing is not allowed in a cask beer, the beer must be consumed in short order as well, with the flavor changing noticeably for better or worse over the course of a few days.
While today we have modern methods of keeping beer cold and fresh for longer, there is something to be said about the good ol’ ways. While CAMRA insists that this is beer is more “real” than the beer we normally drink, it makes me glad that there is yet another way to enjoy beer, real or not. Cask beer is no more real than other beer, but it is different and you might just hate it and you also might just love it. Give it a try at the Cask Beer Fest or if you are ever in Seattle, Machine House Brewery which is known for their traditional cask beers. Thanks for reading!