Brewing the perfect pint

Brewing the perfect beer requires the brewer to use art, craft and science, in a balance of natural ingredients and processes.

Some brewers embrace modern technology while other use more traditional means but whether the brewery is large or small, old or new the process remains the same. The process begins with the malted barley being lightly crushed into a coarse powder called grist.At this stage, other cereals - including flaked maize, unmalted barley and wheat can be introduced, if required by the brewers recipe to produce particular characteristics of flavour or colour or appearance. Darker malts are used for stouts.

In general, around 90 per cent of the total grain used in the UK is malted barley. The grist is transferred to a large vessel called a mash tun, where it is mashed with hot water (similar to the process of making a cup of tea). The natural sugars in the malt dissolve in the water (brewers always call this water liquor), and eventually a sweet brown liquid is run off. The wort, as it is called, is then boiled with hops in large vessels, known as coppers.

The next stage is fermentation, the most critical process of all. The hopped wort is cooled and run into fermentation vessels. Yeast is added, and it begins to convert the natural sugars into alcohol, carbon dioxide and a range of subtle flavours.

Historically, all British ales and stouts were fermented with a yeast that rose to the top of the beer, and in many cases this method is still used. These top fermenting beers develop cloud like, foaming heads. When the yeast has done its job, the head settles into a thick, creamy crust, protecting the beer from air.

Lagers are fermented with a different type of yeast which works at colder temperatures, and which sinks to the bottom of the fermenting vessel. Known as bottom fermentation, to ensure hygienic conditions, enclosed fermenters are used with a conical base, in which the yeast settles into the base.

These days many ales are also fermented in closed conical fermenters. Before a beer leaves the brewery it must be conditioned. The conditioning process differs according to how the beer is to leave the brewery. For cask conditioned beers (real ales), the beer goes directly into the cask, barrel or bottle. More hops may be added to the cask (dry hopping) for extra aroma. Finings are added which bind the materials responsible for haze and sink to the bottom, clarifying the beer.

The yeast in the beer is still active, and the beer will undergo a second fermentation in the cask, normally in the cellar of a pub. Cask conditioned beer is a delicate product and, just like the beer undergoing fermentation in the brewery, it is vulnerable to attack from all kinds of contamination by wild yeasts and other micro-biological organisms. Other beers are bought to condition in the brewery, some are fined and filtered and some are pasteurised to guard against deterioration from microbes.

They reach the consumer in casks, kegs, bottles or cans. For lagers there is a longer period of conditioning in the brewery at low temperature. The word lager comes from the German word lagern - to store at a cold temperature.

Brewers take great pride in each and every beer they brew. Over 1,200 beers are brewed in Britain with more than 28 million pints drunk every day, beer really is the nation's favourite.