Cask ale vs. Keg Beer: What’s the Difference?
With cask beer hitting the headlines recently due to The Craft Beer Channel launching a government petition to protect cask ale and help it gain UNESCO status, and given we proudly serve the only cask ale in Shetland, we thought we’d do a peerie blog on what the differences are beetwen cask and keg as we get asked a lot.
The debate between cask and keg beer is more than just a discussion about storage methods—it’s a conversation about tradition, taste, and craft. While both cask and keg beers have their place in the brewing world, they offer distinctly different experiences. But what exactly sets them apart, and why does it matter?
What is Cask Beer?
Cask beer, also known as real ale, is beer that undergoes secondary fermentation in the cask from which it is served. It is typically unfiltered and unpasteurised, allowing the natural yeast in the beer to continue developing flavours over time. It is served without additional nitrogen or carbon dioxide pressure, meaning it relies on a hand pump for dispensing.
It’s worth noting that cask beer isn’t stored in wooden casks like you see in whisky, but usually metal or sometimes plastic vessels which are also called casks.
What is Keg Beer?
Keg beer, on the other hand, is filtered (in most cases), and carbonated before being sealed in a pressurised keg. This ensures consistency in taste and longevity, as the keg protects the beer from exposure to oxygen and external contaminants. Keg beer is served using a gas system—usually CO2 or a mix of CO2 and nitrogen—to maintain pressure and carbonation levels.
Key Differences Between Cask and Keg Beer
Carbonation: Cask beer is naturally carbonated due to secondary fermentation, resulting in a softer mouthfeel, while keg beer is artificially carbonated, giving it a fizzier texture.
Temperature: Cask beer is typically served at cellar temperature (around 10-13°C), enhancing its depth of flavour, whereas keg beer is usually served colder (2-7°C), making it crisper and more refreshing.
Filtration: Cask beer is unpasteurised, which means it continues to develop flavour even after it’s been put in the cask. Keg beer is filtered and often pasteurised to ensure stability and shelf life (however, there are always exceptions to the rule - this is just generally the case).
Shelf Life: Cask beer is best consumed within a few days of being tapped, as it is more susceptible to oxidation and spoilage. Keg beer, due to its sealed and pressurised environment, can last for weeks or even months without losing quality.
Serving Method: Cask beer is served using a hand pump or gravity, while keg beer is pushed through taps using gas pressure.
If you appreciate a more traditional beer experience, cask beer is your jam. It’s a more “alive” product and is how beer tastes naturally, without the addition of extra fizz and pasteurisation. However, if you prioritise consistency, crispness, and a longer shelf life, keg beer is the way to go.
Lerwick Brewery is proud to be the only place selling cask beer in Shetland! We rotate our real ale pump regularly during the busy months from April – September. If you’re planning a trip to Shetland, pop by our brewery for a tour and to try the UK’s most northerly beer from the UK’s most northerly cask pump!