What is Real Ale?
What makes beer or ale "Real Ale?
Real ale is a living fresh beer that undergoes a natural second fermentation in the cask. Like any natural product, the beer will age and go off, and therefore must be drunk within a strict timescale. It requires care in handling on its way to the pub, and care within the pub to bring it to perfection. However, real ale can reach its full flavour potential, without filtration, pasteurisation and added gas.
Real Ale. The publican is as important as the brewer.
When the real ale arrives at the pub it needs to undergo its secondary fermentation before it can be served. The usual practice is for the casks to be placed in a cool deep cellar. Some pubs keep their beer in a special cool room on the ground floor, a few keep their beer behind the bar - preferably nowadays with some modest external cooling system. Real ale is served at cellar temperature, ideally 12-14C (54-57F), which is somewhat cooler than room temperature. If real ale is too warm it is not appetizing, it loses its natural conditioning (the liveliness of the beer due to the dissolved carbon dioxide). On the other hand if the beer is too cold it will kill off the subtle flavour.
Unlike keg beer which has to be chilled, real ale has flavours you need to taste! Real ale is not 'warm', 'cloudy', or 'flat'. Real ale is served below room temperature, like red wine; served properly it should be entirely clear; if it is kept and served properly it will have enough natural life to be appetizing. How long a beer needs to stand depends on the beer, particularly its alcoholic strength and how vigorously it ferments. Some modern beers have a weak fermentation and may clear within twenty four hours.
That does not mean that these beers have conditioned sufficiently and to serve them as soon as they are clear is not necessarily to serve them at their best. The cask is wedged on its side, to encourage the sediment to sink into the belly. Every cask has two plugs where instruments can be knocked into the cask by force. The cellar person knocks a small wooden peg into one. A hard wood peg seals the cask, a soft wood peg allows carbon dioxide to escape. By alternating hard and soft pegs as needed, the cellar person carefully controls the natural carbonation of the beer. Too high a carbonation and the beer will have a nasty bite, too little and the beer will be flat. When the fermentation is about right, a tap is knocked into the cask at the other entry point. The cellar person will check that the beer is clear, has the right level of carbonation, and has lost the unpleasant flavours associated with beer that is too young. When the beer is ready to serve, the tap is connected to the dispense system. How long the beer lasts depends on its strength - stronger beers are more robust, and may last for weeks, weaker beers are normally drunk within a few days. This is why turnover is so important for quality - ideally the pub sells enough beer that you always drink it at its best.