Beer, like many things we take for granted, is little understood. It is a much more complex drink than many realize. Beer is the juice of the good earth. Its colours, from deep copper to ruby black to pale yellow, reflect the passing of the seasons from bare soil through to the golden harvests of barley and wheat.

The foaming head on a glass hides many mysteries, not least of which are beer's basic ingredients. Malt and hops feature regularly on beer labels and in promotional photographs, but how many recognise the aromatic hop cone, one of the most unusual species in the plant kingdom? Apart from a few Belgian gourmets, nobody eats them today. Besides, how many know what malt really is? It may begin life as a living field of cereal, but the grain has to undergo a complex series of changes - germnination, roasting, and mashing - between its initial harvest and reaching the drinker's glass. There are many different types of malt. Each varies in colour, flavour and sugar content, depending upon the precise methods used to produce it. Each beer has its own 'signature' combination of different malt types.

Yeast is the crucial, 'magical' ingredient and its role in the transformation of the sugar in a brew to intoxicating alcoholremained a mystery for centuries. Again, there are many varieties to choose from, each with its own characteristics - its speed of action, flavour and the amount of alcohol and carbondioxide that it produces.

Hops are a relatively recent addition to the list of essential ingredients. The natural oils that are contained within the hop cones impart the bitterness that many drinkers demand, and help to preserve the brew. There is a mind-boggling range to choose from.

In addition to the basic ingredients, brewers sometimes add more unexpected ingredients to the recipe, such as cherries or ginger, to impart an individual flavour to their particular beer. The result of the vast number of permutations of ingredients available to the beer brewer is a mouth-watering world of choice in the global bar for the lucky beer drinker.

Excerpt taken from 'The Ultimate Encyclopaedia of Wine, Beers, Spirits & Liqueurs'