Cask Ale

What is Cask Ale? Cask Ale, also known as real ale, is an unfiltered and unpasteurised beer that matures through secondary fermentation inside the very container from which it is served, with no added carbon dioxide. Live yeast continues to work in the cask right up to the moment the pint is poured, giving the beer a soft, natural carbonation and a depth of flavour that filtered, force-carbonated keg beers cannot match. The style was codified and championed by CAMRA, the Campaign for Real Ale, founded on 16 March 1971 in Kruger's Bar, Dunquin, County Kerry, Ireland. Often described as Britain's National Drink, cask ale remains a meaningful part of UK pub culture, accounting for 420 million pints sold in 2019, or 13.5% of all pints poured.

Origin and the CAMRA Definition

The term real ale was coined by CAMRA in the 1970s to draw a clear line between traditional living beer and the filtered, pasteurised keg products that had come to dominate British bars. CAMRA was founded by Michael Hardman, Graham Lees, Jim Makin and Bill Mellor, held its first AGM in 1972, reached 5,000 members by 1973, and grew to 30,000 by 1991. The organisation helped launch the European Beer Consumers Union in 1992 and introduced its LocAle scheme in 2007 to promote locally brewed cask beer.

CAMRA's working definition is precise: real ale is 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. For decades this excluded any pub using a cask breather, but in 2018 the policy was relaxed and breather-equipped pubs became eligible for inclusion in the Good Beer Guide.

How It's Served

Cask ale is traditionally dispensed in one of three ways: drawn up by a hand pump, known as a beer engine, poured by gravity straight from the cask resting behind the bar, or, more rarely in parts of the Midlands and Scotland, served via electric pumps. Because the beer is still alive when it reaches the glass, temperature, cellar care, and turnover all play a decisive role in how it tastes.

Casks themselves follow imperial sizes formally designated in 1824. A pin holds 4.5 gallons (20.5 litres), a firkin 9 gallons (41 litres), a kilderkin 18 gallons (82 litres), a barrel 36 gallons (164 litres), and a hogshead a sizeable 54 gallons (245 litres). The firkin remains the most common size seen in British pub cellars.

Cask Versus Keg

The clearest way to understand cask ale is to set it against its keg counterpart. Keg beer is filtered, pasteurised, and force-carbonated with added CO2, producing a stable, consistent product that travels easily and pours the same in any venue. Cask ale takes the opposite approach: it retains natural carbonation from ongoing fermentation, evolves in flavour over the few days it is on sale, and demands skilled handling at the cellar level.

That trade-off, less convenience in exchange for more character, is precisely what cask drinkers seek. The result is a softer carbonation, a fuller mouthfeel, and aromas that express the malt, hops, and yeast more openly than any pressurised system allows.