Cask ale — also called real ale — is beer that completes its fermentation inside the container it is served from and is dispensed without added gas pressure. That single difference shapes everything about the style: how it is brewed, how it is conditioned, how it is poured, and how it tastes in the glass. This guide walks through the brewing process, the traditional steps that prepare a cask for serving, the ways cask ale is dispensed, and what keeps it fresh and in good condition.
What Makes Cask Ale Different
Cask ale is a living, naturally carbonated beer. Instead of being filtered, pasteurised, and pushed out with carbon dioxide or nitrogen, it is sealed in a cask while yeast is still active. The yeast produces the carbonation on its own, and the beer continues to develop slowly until the cask is empty.
- Secondary fermentation: happens inside the cask, not in a separate tank.
- Natural carbonation: created by yeast, giving gentle, soft bubbles.
- No external gas pressure: served by gravity or by a hand pump.
- Unfiltered and unpasteurised: the beer remains a living product.
- Cellar temperature: traditionally cool rather than ice cold.
How Cask Ale Is Brewed
The Base Ingredients
Cask ale is typically made from four ingredients: malted barley, water, hops, and yeast. Some brewers add wheat, oats, roasted grains, or sugar to adjust flavour and body. A clarifying agent may also be used later to help the beer drop bright.
The Brewing Process
The first stages are the same as for most beers. The difference appears at the very end.
- Milling and mashing. Malt is crushed and steeped in hot water so enzymes convert starch into fermentable sugars.
- Sparging. Hot water rinses the remaining sugars from the grain bed.
- Boiling. The sugary liquid, now called wort, is boiled with hops for bitterness, flavour, and aroma.
- Cooling. The wort is chilled to a temperature the yeast can tolerate.
- Primary fermentation. Yeast converts sugars into alcohol and carbon dioxide over several days.
- Racking into the cask. The beer is transferred while still slightly active, sometimes with a small amount of priming sugar and hops.
Secondary Fermentation in the Cask
Inside the sealed cask, the remaining yeast continues working. It consumes the residual sugars, produces a gentle natural carbonation, and rounds off the beer’s flavours. Dry hops may be added at this stage for extra aroma. A fining agent is often included so suspended particles bind together and settle to the bottom, leaving the beer clear.
This stage takes days to weeks. The beer arrives at the point of sale already partly conditioned, but it still needs careful handling before it is ready to drink.
Cask Conditioning: Getting the Beer Ready to Serve
A cask that has just been delivered is not ready to pour. It needs time and a few simple steps.
1. Settling
The cask is placed on its stillage, usually with the tap at the bottom, and left undisturbed. Sediment, yeast, and finings sink to the base. Moving the cask during this period stirs everything back up, so it is left alone for a day or more — often longer for stronger beers.
2. Venting
A soft, porous peg is driven into the shive at the top of the cask. This allows excess carbon dioxide to escape while air is kept out. Venting prevents the cask from becoming over-pressurised and lets the beer reach the right level of condition.
3. Tapping
Once the beer has settled and vented, a tap is driven into the keystone at the bottom. The first runnings are usually discarded because they contain sediment. A hard, non-porous peg then replaces the soft one to seal the cask, keeping the beer protected from oxygen while it is served.
4. Checking Condition
A well-conditioned cask ale has a light, natural sparkle and a soft head. Too much pressure makes it foamy and lively; too little leaves it flat. Cellar staff monitor this and adjust venting accordingly.
Common Cask Sizes
- Pin: about 4.5 imperial gallons (roughly 20 litres).
- Firkin: about 9 imperial gallons (roughly 41 litres) — the most common size.
- Kilderkin: about 18 imperial gallons.
- Barrel: about 36 imperial gallons.
Smaller casks are popular because the beer is fresher for longer once opened.
How Cask Ale Is Served
Dispense Methods
There are two traditional ways to pour cask ale. Gravity dispense means the cask sits above the bar and the beer flows straight from the tap. Hand pump dispense uses a manual pump, often called a beer engine, to draw beer up from a cellar. Both methods rely on the beer’s own gentle pressure rather than forced gas.
Serving Temperature
Cask ale is served at cellar temperature, roughly 11–13 °C (52–55 °F). This is cooler than room temperature but warmer than chilled lager. The warmer serving temperature allows malt and hop aromas to show, which is why cask ale is often described as more flavoursome than heavily chilled beer.
Carbonation and Head
Natural carbonation is gentle, so the head is softer and less fizzy than keg beer. Some servers use a restrictor nozzle on the pump to create a thicker, creamier head. Others pour without one for a lighter foam. Both approaches are simply regional and stylistic preferences; neither changes the beer itself.
Pouring and Glassware
A clean, dry glass is essential — traces of grease or detergent kill the head. The beer is poured in one steady motion, or topped up after a short pause if a larger head is desired. It is then left to settle briefly before drinking.
Cask Ale vs. Keg Beer
- Carbonation: cask is naturally carbonated; keg is carbonated with added gas.
- Filtration: cask is typically unfiltered; keg is usually filtered and pasteurised.
- Dispense: cask uses gravity or a hand pump; keg uses gas pressure.
- Temperature: cask is served cool; keg is often served colder.
- Shelf life: cask is best within a few days of opening; keg lasts much longer.
Common Styles of Cask Ale
- Bitter: the classic session beer, amber to copper, balanced hops.
- Mild: dark, low in alcohol, malty and easy drinking.
- Golden ale: pale, crisp, and hop-forward.
- Porter and stout: dark, roasty, and full-bodied.
- Old ale and strong ale: richer and higher in alcohol, often aged.
- India pale ale: stronger and hoppier, in the traditional cask format.
Keeping Cask Ale Fresh
Once a cask is tapped, oxygen begins to affect the beer. A tapped cask is usually best consumed within two to four days, depending on the strength of the beer and the cellar conditions. Cooler cellars and stronger beers keep longer. Careful hygiene, clean dispense lines, and minimal disturbance all help the beer stay in good condition from the first pint to the last.
Serving Cask Ale at Home
Cask ale can be enjoyed at home, though it requires more planning than a bottle.
- Buy a cask size you can finish within a few days.
- Let it stand undisturbed in a cool place for at least 24 hours.
- Vent the cask gently, then tap it once the beer has settled.
- Keep it cool and avoid moving it.
- Pour steadily into a clean glass and drink while fresh.
Frequently Asked Questions
Is cask ale supposed to be warm? No. It is served cool, around 11–13 °C, which is warmer than lager but still noticeably chilled.
Why does cask ale look flat? Its carbonation is natural and gentle. A light sparkle rather than heavy fizz is normal and intentional.
How long does an opened cask last? Typically two to four days once tapped, depending on strength and storage conditions.
Is cask ale the same as draught beer? Not exactly. Draught beer can be cask or keg; cask ale specifically refers to beer conditioned and served from the cask without added gas pressure.
Conclusion
Cask ale is defined by where its fermentation finishes and how it is poured. Brewed like other beers but racked into the cask while still active, it carbonates itself, clears naturally, and is served cool by gravity or hand pump. The result is a softer, more aromatic pint that changes subtly as the cask empties. Understanding the brewing, conditioning, and serving steps makes it easier to appreciate why careful handling matters so much — and how to enjoy cask ale at its best. For more straightforward guides on drinks, food, and everyday how-tos, explore the other articles on this site.