Types and styles of beer

A great many beers are brewed across the globe. Local traditions will give beers different names, giving the impression of a multitude of different styles. However, the basics of brewing beer are shared across national and cultural boundaries.
The British beer writer Michael Jackson wrote about beers from around the world in his 1977 book The World Guide To Beer and organised them into local style groups based on local information. This book had an influence on homebrewers in United States who developed an intricate system of categorising beers which is exemplified by the Beer Judge Certification Program.
The traditional European brewing regions — Germany, Belgium, the United Kingdom, Ireland, Poland, the Czech Republic, Denmark, The Netherlands and Austria — have local varieties of beer. In some countries, notably the USA, Canada and Australia, brewers have adapted European styles to such an extent that they have effectively created their own indigenous types.

Categorising by yeast

A common method of categorizing beer is by the behaviour of the yeast used in the fermentation process. In this method of categorizing, those beers which use a fast-acting yeast, which leaves behind residual sugars, are termed ales, while those beers which use a slower and longer acting yeast, which removes most of the sugars, leaving a clean and dry beer, are termed lagers.
Differences between some ales and lagers can be difficult to categorise. Steam beer, Kölsch, Alt, and some modern British Golden Summer Beers use elements of both lager and ale production. Baltic Porter and Bière de Garde may be produced by either lager or ale methods or a combination of both. However, lager production results in a cleaner tasting, dryer and lighter beer than ale.

Ale

Cask ales
A modern ale is commonly defined by the strain of yeast used and the fermenting temperature.
Ales are normally brewed with top-fermenting yeasts (most commonly Saccharomyces cerevisiae) , though a number of British brewers, including Fullers and Weltons, use ale yeast strains that have less pronounced top-fermentation characteristics. The important distinction for ales is that they are fermented at higher temperatures and thus ferment more quickly than lagers.
Ale is typically fermented at temperatures between 15 and 24 °C (60 and 75 °F). At these temperatures, yeast produces significant amounts of esters and other secondary flavour and aroma products, and the result is often a beer with slightly "fruity" compounds resembling apple, pear, pineapple, banana, plum, or prune, among others. Typical ales have a sweeter, fuller body than lagers.

Lager


A stein of lager
Lager is the English name for bottom-fermenting beers of Central European origin. They are the most commonly consumed beers in the world. The name comes from the German lagern ("to store"). Lagers originated from European brewers storing beer in cool cellars and caves and noticing that the beers continued to ferment, and also to clear of sediment. Lager yeast is a bottom-fermenting yeast (e.g., Saccharomyces pastorianus), and typically undergoes primary fermentation at 7–12 °C (45–55 °F) (the "fermentation phase"), and then is given a long secondary fermentation at 0–4 °C (32–40 °F) (the "lagering phase"). During the secondary stage, the lager clears and mellows. The cooler conditions also inhibit the natural production of esters and other byproducts, resulting in a "cleaner" tasting beer.
Modern methods of producing lager were pioneered by Gabriel Sedlmayr the Younger, who perfected dark brown lagers at the Spaten Brewery in Bavaria, and Anton Dreher, who began brewing a lager, probably of amber-red colour, in Vienna in 1840–1841. With improved modern yeast strains, most lager breweries use only short periods of cold storage, typically 1–3 weeks.

Lambic beers: spontaneous fermentation

Lambic beers, a speciality of Belgian beers, use wild yeasts, rather than cultivated ones. Many of these are not strains of brewer's yeast (Saccharomyces cerevisiae), and may have significant differences in aroma and sourness. Yeast varieties such as Brettanomyces bruxellensis and Brettanomyces lambicus are quite common in lambics. In addition, other organisms such as Lactobacillus bacteria produce acids which contribute to the sourness.

Pale and dark beer
The most common colour is a pale amber produced from using pale malts. Pale lager is a term used for beers made from malt dried with coke. Coke had been first used for roasting malt in 1642, but it wasn't until around 1703 that the term pale ale was first used.
In terms of sales volume, most of today's beer is based on the pale lager brewed in 1842 in the town of Pilsen, in the Czech Republic. The modern pale lager is light in colour with a noticeable carbonation, and a typical alcohol by volume content of around 5%. The Pilsner Urquell, Bitburger, and Heineken brands of beer are typical examples of pale lager, as are the American brands Budweiser, Coors, and Miller.
Dark beers are usually brewed from a pale malt or lager malt base with a small proportion of darker malt added to achieve the desired shade. Other colourants — such as caramel — are also widely used to darken beers. Very dark beers, such as stout use dark or patent malts that have been roasted longer. Guinness and similar beers include roasted unmalted barley.