Thanks to David Jensen at Menuism, I am beginning to understand a little more about the cask ale that I drank at The Great Dane Brewery and Pub last night. (To read the entire article, click on the link above!)
What is Cask Conditioned Beer?
Cask conditioned beer, or cask ale, is beer that is both conditioned in and served from a cask. Up until the beer is placed in the cask, the brewing process is exactly the same: mash, boil, ferment. After the beer finishes primary fermentation, it is placed in a cask with finings (a substance that causes particles suspended in fluid to drop out of suspension) to help clarify the beer. Often sugar will also be added to the cask to aid with the secondary fermentation, and sometimes even extra hops. The beer is then conditioned in the cask. Conditioning is the penultimate stage in the brewing process when the beer matures, clarifies, and carbonates. In the case of cask conditioned beer, there is a small amount of yeast remaining in the beer that causes secondary fermentation, which carbonates the beer. The conditioning time depends on the beer style and can last between 24 hours and 16 days. Traditionally, the casks are conditioned at the pub by the publican, but can also be conditioned at the brewery and shipped out when ready. When the cask beer is ready, the yeast and other sediment settles to the bottom, the beer is carbonated, and served directly from the cask. Cask ale is always unfiltered, unpasteurized, and always best fresh.
Some of the most common styles of beer found in a cask are English-styles: bitter, mild, brown, pale, ESB, and so on. However, I have seen other styles, such as American IPA on cask like Ballast Point Sculpin IPA, and I’ve also tried Rogue Chocolate stout on cask.
But what’s the difference?
Since cask conditioned ales are not filtered and not pasteurized, they contain live yeast that continues to add complexity, new flavors, and new aromas to a beer. The exact differences vary from beer to beer. The texture of a cask conditioned beer on your palette is often more creamy and smooth than its non-cask counterpart. Furthermore, there are a few beers that are only available on cask.
Cask conditioned beer is dispensed directly from the cask in one of two ways. First is simply by means of gravity, or gravity dispense. The cask is laid on its side and a spigot is attached through one of the openings. If you attend a festival or special event of cask conditioned beer, this is likely what you will see.
The second method for dispensing cask beer is likely what you will see at a pub that regularly serves cask ale: a beer engine, also known as a hand pump. The beer engine allows the cask to be in a remote location, preferably under the bar in the cellar (or some other temperature-controlled area). The beer engine is a pump, usually manually operated, that siphons beer into an airtight piston chamber. Pulling down on the pump raises the piston, drawing beer along with it, up through the spout into your glass. The spout is often a swan-neck spout and sometimes fitted with a “sparkler” to aerate the beer and create a more foamy head. Since beer sits in the piston between servings, good pubs will discard the first pull of the day.