BHU Week 19: Differences between cask and keg

As we've been off enjoying the beer festivals here at Beer Hawk University, there's one thing we should talk more about: what's the difference between cask and keg?

We're always impressed by the stacks and stacks of kegs and casks behind the bars at our favourite beer festivals. With all those hoses, lines and racking--that's a lot of hard work. And that's before the punters make their way in the door! While the volunteer or brewer fills your glass from the kegs or the casks behind them, have you thought about what makes it different? No? Too busy enjoying to wonder about such things? Well, let's talk about what makes cask and keg the same, but different.

Cask

Cask beer: that brilliant institution that British beer culture is based on. But just how does a cask ale get from the brewery to your glass? Hint: the publican

BHU Week 19: Differences between cask and keg

As we've been off enjoying the beer festivals here at Beer Hawk University, there's one thing we should talk more about: what's the difference between cask and keg?

We're always impressed by the stacks and stacks of kegs and casks behind the bars at our favourite beer festivals. With all those hoses, lines and racking--that's a lot of hard work. And that's before the punters make their way in the door! While the volunteer or brewer fills your glass from the kegs or the casks behind them, have you thought about what makes it different? No? Too busy enjoying to wonder about such things? Well, let's talk about what makes cask and keg the same, but different.

Cask

Cask beer: that brilliant institution that British beer culture is based on. But just how does a cask ale get from the brewery to your glass? Hint: the publican (or festival cellarmaster) have a lot to do with it.

Step One: The brewer brews a beer. They don't filter it and they don't pasteurise it. A cask is filled with this beer which is still alive with yeast. This is called racking.

Step Two: Finings are added to the beer which, when finished conditioning, will clarify the beer. Isinglass (or fish bladders) or Irish moss are two sorts of finings used to produce clear beer, the latter being suitable for vegetarians. The cask opening is sealed with a plastic stopper called a "shiv".

Step Three: The beer conditions in this cask for a week or two longer (or more!) This process is called secondary fermentation. Any residual yeast in here will eat up remaining sugars and give off CO2 which can't escape. This process gives a cask ale its distinctive creamy, delicate carbonation.

Step Four: Once ready, it's off to the pub! The brewer's work is done here. Now it's up to the cellarmaster.

Step Five: When it's time for more cask ale on the bar, the cask is put up on racking which is called "stillgating". The large hole where the shiv is is on top and the cask is tilted on an angle so that the sediment collects below the tap and doesn't get into your glass.

Step Six: The shiv has a wooden peg driven through it with a mallet. The tiny holes in the wood allow air to escape (but not too much!) As the air escapes, the suspended finings drops to the bottom collecting any residual yeast and sugar on their way down. This process is called "dropping bright". The beer is now clear and "bright". This process may take up to three days.

Step Seven: Once the beer is bright it is ready to be tapped. The small hole on the end of the cask, called a keystone, has the tap driven through it. Lines from the tap are strung up to the bar above along a tap line snake.

Step Eight: When a beer is ordered, the bar staff pulls firmly and quickly on the cask handle which is connected to a hand-powered hydraulic pump. This action and the pump works with gravity to "pull the pint" into the glass from the cask in the cellar below the bar. As if by magic. 

Trick to pulling the perfect pint:

Put the spigot at almost the bottom of the glass. Give the pump handle one quick, full pull allowing a small head to form. Remove the spigot from below the surface and push the pump handle back. Wait about 5-8 seconds. Repeat about three or four more times until the glass just starts to slightly overflow. Allow to rest for a little bit to ensure a nice head and clear beer has been poured. Wipe off the glass and enjoy!

 *In Northern England the nozzle will have a "sparkler" on the end. This little piece essentially frothes the beer as it passes through. We think this makes a prettier, denser head.

That's a lot of care, work and expertise that goes into our humble pint. Now imagine trying to do enough of that for 50,000 people at the Great British Beer Festival? Phew. We need a beer.

Keg

If you've got a bad taste in your mouth (pun intended) for keg beers, that's probably because the beery nightmare that consisted of nothing other than bland lagers is coming screaming back at you. That's not the case anymore, however. Indeed, there are many glorious beers that are served on keg. So how does keg beer work?

Step One: The brewer brews a beer. The fermented beer is transferred to the keg. Sometimes it's filtered and pastuerised, other times just filtered, or just popped into the keg as is.

Step Two: Beer is carbonated with pure CO2 by way of directly sending the gas into the beer to create carbonation. This is called "force carbonation."

Step Three: It's off to the pub! The beer is done at the brewery and is now one step closer to the glass. With the correct tools, you could drink it out of the keg right now if you wanted to. It's ready!

Step Four: The kegged beer is in the cellar and ready for dispense to the bar. The beer needs a mixture of gases--nitrogen and CO2--to get the beer to the bar. Canisters of the gases are supplied in the cellar and set to an appropriate Psi. This is usually done by the gas supplier and not the publican.

Step Five: The keg is connected to the gas with a "coupler". This bracket has two hoses: one attaches the gas line to the keg and the other is the "liquid out" line. Once connected, the gas put pressure on top of the beer so that when the bar staff flips the keg tap is pushes the beer through the liquid out line. 

Step Six: The beer is pushed out through the lines up to the bar. These tubes usually run through a chiller and then alongside a line filled with chilled water on the way up to the bar. This ensures a proper temperature, around 3-7?C. 

If your beer is frothing with a fury and fobbing over, it's too warm. Make sure the chiller in the cellar and line temperature is not too high. If the temperature is ok, make sure that you open the faucet the whole way when pouring into the glass. Even if it's closed a little bit, it will agitate the pour.

*Keeping the lines clean, the gas at its proper pressure and the whole system at the correct temperature (and don't forget to pour it correctly into a clean glass!) will ensure that each glass of kegged beer is as delicious as the brewer wanted it to be. 

So making and serving keg beer isn't as complicated as that on cask but it still takes a bit of expertise to make sure that each glass served is beautiful. While kegged beers get a bad rap, we think that's unfair. Many styles are better suited to the fizzier mouthfeel and there's no better way to experience a beautiful hop bouquet in an American IPA than having it lifted right to your nose on a wave of bubbles. Sounds pretty good, doesn't it?

Wow, there's so much to learn and know about this beautiful drink. We hope you have a new appreciation for what the staff and crew at your favourite beer festival goes through to give you a fantastic time!

We'll see you next week at Beer Hawk University when we have another little taste comparison between some of our favourite beers. Unit 2 is a bit shorter than last time so we're not far away from review and quizzzzzz! See you next time!