New breweries are constantly opening, introducing new beers and, occasionally, some breweries are absorbed by others or go out of business. As such there is never likely to be an absolutely current list of all available beers. However a good understanding of beer starts with understanding style and the classic beer styles we know today all originated from the northern part of central and Western Europe. After centuries of brewing, their main stylistic differences are well understood.
Essentially, beer falls under one of three different categories: lagers, ales or specialty beers. All beers share the same basic ingredients: water, malted barley, hops and yeast. In its simplest terms, the factors that go into deciding the type and style of beer to be made are the type and quantity of malt being used, the type, amount and method used when adding the hops, and the strain of yeast used to ferment the beer.
An ale yeast is called top fermenting because of its tendency to gather (flocculate) at the surface of the brew during the first few days before settling to the bottom. Fermentation for ales requires warmer temperatures (typically 60 to 75 degrees °F) for the yeast to multiply and work. Ales are usually quicker to brew, higher in alcohol and are fuller and more complex.
The lager yeast is bottom fermenting. It simply flocculates (not at the surface) and sinks to the bottom. Lager yeasts require cooler temperatures during fermentation (typically temperatures below 55 degrees °F) to perform their work. Lagers tend to be lighter in color (although different types of water can produce red or darker lagers). They also usually taste drier than ales. On the whole they are less alcoholic and complex. But they are popular. Over the last couple of centuries lagers have risen to become the most popular beer type in both the U.S. and the rest of the world.
Specialty beers can be either ales, lagers, or a hybrid of the two. They contain other ingredients that cause them not to fit into a true ale or lager style - but into the category of "specialty" beer.
Lagers main varieties
Light
Dark
Pale
Pilsner
Lager