In the UK, cask ale refers to beer that is served without additional carbon dioxide or nitrogen pressure and is
more often than not referred to as Real Ale. In the US, cask ale is used to describe conditioned beer that is
unpasturised, unfiltered and served from a cask. The term cask ale is now often used to cover bottle conditioned
beer as well.
Keg beer on the other hand is used to describe beer that is served from a pressurised keg. Quite often, keg beer
is also pasturised and filtered in order to make the yeast inactive. This effectively increases the shelf life of
the beer but does so at the expense of flavour. Keg beer is what is served in most UK pubs and is often referred to
as draught beer. However, you will quite often come across pubs that also serve cask beer as well, mainly due to
Both cask ale and keg ale are brewed in exactly the same way. In fact, the resulting brew could easily be used
for bottled beer, keg beer or cask beer. The difference comes in when fermentation has been completed and the brew
is left to condition.
Cask ale is placed into the cask in it's natural state together with finings such as Irish Moss seaweed or
Isinglass which is the swim bladder of fish. Finings are added to the cask in order to drag down the yeast and also
clear the beer. Additional sugar and/or hops may also be added before the cask is sealed and shipped off to the
pub. The beer in the cask will continue to condition itself for a while but its lifespan is dependant on the type
of beer. Dark strong bears will last a lot longer than light beers that do not take so long to mature and settle.
Consequently, light beers need to be tapped and used immediately whereas stronger beers can be kept for several
months before being tapped.
Ideally, cask ale should be served at a cool temperature rather than cold in order to bring out the flavour of
the beer. Some pubs will run cask ale lines through a cooler system first, which will ultimately make the beer too
cold once it reaches the glass. However, if the pub or brewpub is run by a landlord who understands cask ale, the
beer will always be served at the optimum temperature which is cool but not too cold.
Cask ale has a more wholesome and fresher smell to it than keg beer - exactly as good old fashioned real ale
should smell like. As well as being somewhat tasteless, many keg beers do not have too much aroma about them
The flavour of cask ale is very much the same as the aroma although the taste is a lot more noticeable - very
fresh and delicate. As cask ale has little or no carbonation, more flavour will hit your taste buds as opposed to
keg beer which is full of CO2 bubbles. These bubbles have no taste of there own but because that is what is
bursting on your tongue, the beer will not make contact and hence the reason why keg beers give a poor taste
The mouthfeel is probably the most important aspect of cask ale. For one thing, cask ale should definitely not
be fizzy - if it is, you have probably been served keg beer. There should also be a natural feel about beer from a
cask - a feel that makes you want to drink it.
If you are used to drinking keg beer, you may just find the mouthfeel of cask ale flat and boring to begin with.
However, once you have gotten used to cask ale, it is unlikely that you will revert back to drinking keg beer as
there is little or no comparison between the two when it comes to taste, aroma and mouthfeel.