Cask-Conditioned Real Ales
by Steve Lonsway
There is something about sitting in an English pub enjoying a pint of real ale. A wood fire crackles, there is quiet chatter amongst the locals as a few well-behaved dogs lie patiently at the feet of their masters who are comfortably seated at the bar. As a guest orders another pint, the barkeep grabs the top of an ornate porcelain handle, pulling it gently forward with the awaiting glass underneath. After two swift pulls, the glass is filled to the brim and placed on a coaster in front of the patron. The head is light, the color is pale or amber, and the aromas inspire.
But what is that contraption the bartender pulled to fill the glass? It’s called a beer engine or hand pump and it pulls the beer from the cask located in the cellar to the bar and into the glass. Sounds simplistic, but so much went into that pour.
First, the Brewmaster must construct the recipe using traditional ingredients: malt, hops, yeast, and water. Then, near the end of the fermentation process, he or she must carefully transfer the suds into a cask and add a small amount of isinglass (used as a clarifier). It is important for fermentation to still exist within the cask so that the brew can self-carbonate with a by-product of fermentation – carbon dioxide. Once the beer is in the cask, a two piece bung is placed into the cask. After a specific amount of time, a soft spile or peg is placed into the center of the bung which will allow excess gas to escape. When the Brewmaster feels the time is right, they will replace the soft spile with a hard one that isn’t porous so that the carbon dioxide can no longer escape.
Now the beer is ready to make its voyage to the pub. Once it is received, the publican will place it on a special rack or stillage and a specially designed faucet is pounded into place through the keystone at the front of the keg. A soft spile replaces the hard one and the line is attached to the faucet. A soft spile is required so that ambient air can enter the cask when the beer is pulled from the keg otherwise it would airlock. Some pubs will apply a cask breather which replaces the ambient air with a gentle layer of CO2 which allows the cask to remain fresh for a longer period of time. As the bartender pulls that magic handle, the beer is drawn from the cask and it flows through the line, to the beer engine, through a sparkler tip, and into the glass.
The British take their real ales very seriously, so much so that there is a campaign for real ales called CAMRA. Their definition of real ale is “Beer brewed from traditional ingredients, matured by secondary fermentation in the container from which it is dispensed, and served without the use of extraneous carbon dioxide”. Check out their website for more information. Camra.org.uk