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What's the difference between cask and keg?

Date: 08 Oct 2014
The range of beers on our pumps and in our tanks has expanded in recent years, ranging from our traditional real cask ales to the kegged modern craft beer.

But what is the difference between cask and keg beer? We turned to award winning beer writer Ben McFarland for help.

When the good folk at Fuller’s Brewery asked me to write about "The Difference Between Cask Ale and Keg Beer”, I did what any hard-hitting, sword-of-truth wielding newshound would do. I turned on the internet and typed ‘cask versus keg” into the Google contraption (other search engines are available).

The online scene resembled a giant cartoon brawl – a massive Beano-esque cloud of dust with assorted fists, feet and colloquial expletives emerging from it at various angles. While some understandably dismiss the whole “cask v keg” mass debate as a mere storm in a dimpled mug, there are a lot of people who become very passionate, and indeed rather angry, about the way in which their beer is stored and poured in their local pub.

In one corner, there’s cask ale. Cask ale is, without exception, Britain’s finest ever invention. That’s not opinion, that’s fact. It’s better than penicillin, the Internet, the corkscrew, Marmite and Viagra put together - and I should know as, last Friday night, I actually did put them all together and ended up, rather embarrassed, in A&E. With the benefit of hindsight, I should have chosen a nice pint of Chiswick.

What is Cask Ale? 

Anyway, cask ale. What is it? Cask ale, also known as cask-conditioned beer or ‘real’ ale, is beer that undergoes secondary fermentation in the barrel. Brewers of cask ale don’t interfere with it, they don’t filter it and they don’t pasteurise it. All they do is put fresh live beer straight into the barrel where, still in unfinished form containing lots of lovely fruity residual yeast, it remains alive and kicking until it lands in your glass.

Cask conditioning is to beer what the Methode Champenoise is to wine. Just as Champagne evolves in the bottle, so too does cask ale mature and ripen in the barrel. The live yeast not only nibbles away at the sugars, turning them into alcohol and creating soft carbonation, it also rounds off rough flavour edges and brings greater depth of flavour.

All this tends to happen in the pub cellar and the quality of your pint depends hugely on how well the pub looks after it. There’s a real art to it and, as a master cellarman, publicans ensures that the cellar is spotless and that the beer is stored at the right temperature and pulled through pristine pipes with rapid regularity – which it will if the beer tastes bloody lovely.

Using a hand-operated hydraulic pump, the beer is then drawn up from the cellar into the glass. The beer should never be flat. It should be gently effervescent, there should be a light prickle on the palate and it should be topped with a lovely white head, the size of which depends very much on where you’re drinking it.

If a pint loses its head in some parts of the country, then the drinker will too! Geordie drinkers, for example, like it large; Yorkshire drinkers like a tightly-knit top while London landlords layer a thin frothy head on a pint of real ale.

Now, there are few finer things in life than a pint of cask ale which has been skilfully brewed and lovingly looked after and, by golly, every beer lover around the world should doff their cap in the direction of the Campaign for Real Ale – the biggest consumer organisation in the country who have been valiantly championing cask ale in its most traditional, purest form since the 1970s. Without them, cask ale would be in a coffin – of that there’s no doubt.

That said, it’s worth remembering what the alternatives were in the 1970s. Back then, keg beer was properly and consistently dreadful and, lest we forget, there were some seriously lousy lagers out there too.

What is Keg Beer?

“Keg beers” had become a derogatory term for inferior ales served using cold conditioning, pressurised tanks, filtration and the use of extraneous carbon dioxide techniques that, ironically, had first been used to produce the lovely legendary lagers brewed in mainland Europe back in the late 19th century.

Today, however, this is not the case. Keg beer has shed its shameful past, the scars of Smoothflow have finally healed and it’s no longer synonymous with industrial conglomerates. Keg beer has discovered a new lease of life and become integral in the thriving craft beer scene in this country and beyond.

The use of carbon dioxide and nitrogen may quiver the livers of cask ale drinking die-hards but, I’ll level with you, I love a bubble or two in my beer. When I wrote “Good Beer Guide West Coast USA” (published by CAMRA!) with Tom Sandham a few years ago, we spent three months on the West Coast of America drinking awesome keg-conditioned ales whose flavour was enhanced with a bit of fizz.

Our go-to beer when we were over there was Sierra Nevada Pale Ale, a Californian classic that, in my opinion, suits keg better than cask - the distinct Cascade hop comes through with more clarity when served at a lower temperature and some sparkle to it.

We also found that keg suited beers which were hoppier and stronger – the effervescence would rid the tongue of hop resins and prepare it for another gulp. That said, it wasn’t long before we were hankering after a humble hand-pulled British bitter displaying nuanced bitterness and balance – without the burps!

As someone who grew up in West London sipping pints of London Pride, I recently approached a keg-version of the beer with trepidation but I needn’t have worried, the carbonation made the malt more mellow and heightened the hop aroma. Was it better than the cask version? I would never say that, not after all those happy years we spent together.

Traditionalists may still have concerns about keg and it would be a beer drinking disaster if hand-pulled pints were usurped by their gas-driven counterparts but, as it stands, the two seem to be thriving just fine, shoulder-by-shoulder, on the bar tops of the nation’s better pubs and bars.

Whether cask or keg, beers can be both delicious and disappointing. The devil is in the drink and not, it seems, the dispense.

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