Cape Cod Beer’s Cask Series produces a new Real Ale offering monthly!
Click here and choose “Cask Series” to learn about past casks and look for a new one every month from Cape Cod Beer! Scroll down to read more about Cask Beer.
What is cask beer and why are we so excited about it?
Brewer, Joe Rinaldo writes:
“Why is cask (sometimes referred to as ‘Real Ale’) so special?
1) A cask is different from a traditional keg and allows the beer to be conditioned and served.
2) Cask beer has a different fermentation process that creates a unique flavor and texture.
3) Cask beer is always unfiltered & unpasteurized. It’s a living product with a short shelf life, difficult to transport and therefore a rare find!
To begin with, the vessel from which it is served is special. A cask can come in many different sizes, similar to traditional kegs. Each of these sizes has two holes, compared with one on a traditional keg. Both holes are called, “bungs,” and both are filled with unique instruments: the larger side-bung is filled with a plug called a shive, while the smaller hole on the top is filled with a plug called a key. These two plugs are important to how cask is served. The tap is hammered thru the key, where beer is poured. The shive is slightly different. In the center of the shive, there is a smaller plug called a tut, which is hammered into the cask by a spile. The spiles are used to seal the cask during conditioning, or to allow air to flow into the cask during serving, which gives us the two names, hard spile and soft spile, respectively. All of these plugs, spiles, and taps are used to properly condition and serve the delicious beer inside the cask. Before all of that, though, the beer must be properly prepared and the cask must be filled.
There are two methods of making cask beer. The first method involves taking beer that is not fully finished fermenting directly from the fermenting tank. Using the specific gravity as our guide while following the progress of fermentation, we will fill our cask with still-fermenting beer (usually 1-2 ° plateau above finishing gravity). This method allows for the freshest beer possible to be put into the cask, a technique and a flavor that is unique to cask beer.
The second method involves only slightly more labor. If using still-fermenting beer is not an option, an outside yeast- source and an source of sugar can also be added to a cask of already-fermented beer (finishing gravity has already been achieved). Once fermentation is complete and the beer has been crashed down to near freezing (a process for a different explanatory essay), a keg of beer can be removed and is left at room temperature to allow the beer to warm. After the beer warms up, the cask is filled directly from the keg. During the process of filling, a small amount of sugar and a small amount of active yeast is added to the cask as well.
In both methods, the cask is filled through the larger side bung and then sealed by hammering a shive into the aforementioned bung (the key bung has obviously already been filled). The cask is then left at fermentation temperature (60-70°F) for around one week, although that timeline can bee adjusted based on the beer in the cask. During this time, fermentation continues or starts again, but now in a sealed container. This allowed the carbon dioxide gas created during fermentation to remain in solution, carbonating the beer very slighty. After this period of secondary fermentation, the beer is then placed in the fridge to crash down to around 38°F (WHICH IS THE TEMP THAT ALL BEER FRIDGES SHOULD BE AT). This cooling allows any other proteins and yeast still in solution to coagulate and fall to the bottom of the cask. This period lasts a week or more depending on the beer. When finished, the tap is smashed through the key bung and then the tut is smashed through the shive. The result, hopefully, will be a very lightly carbonated and slightly warm beer (around 50-54°F) that is very traditional to England, but has found a niche-following within the American craft beer movement.”