Ales and lagers are the two main subdivisions of beer. Ales are beers, lagers are beers. Generally, a beer is an alcoholic beverage derived from fermented grain. Most beer comes from barley, with a significant minority deriving from wheat. Most American mass-produced beers also include adjuncts, like rice and corn. Rye has also become popular in recent years. Beverages that are produced using fermented fruit are, in general, classified as wines or ciders. with fruit-flavored beers, the fruit is usually a flavoring, while there is still a grain base that is being fermented. Fermentation takes place due to the action of microorganisms (yeast) upon sugar, which they convert into alcohol.
Prior to the scientific advances that led to the discovery of bacteria and other microorganisms in the 1800's, fermentation was poorly understood. The various yeasts that catalyzed fermentation were "wild" yeasts that were to be found in the environment where the brewing took place. It was not until the last several century or so that yeast strains were cultivated and stored to ensure standardization in the brewing process. The Lambic style is one of the few that still employ the use of wild yeasts.
Of the two main categories of beer, ales are the oldest. The naturally occurring yeasts were "warm fermenting" or "top fermenting", meaning that a certain amount of heat was involved and the used up yeast floated to the top of the ale once the fermentation was done. For centuries, perhaps millennia, all beers were what we would classify as ales.
Before the science of microbiology was developed, the reason, not only for fermentation, but for spoilage, was not understood. Some brewers in the colder regions of Germany, however, discovered that keeping an ale cold would extend its life. They began the custom of brewing a batch in March, before it started warming up in the Spring, and storing it in a cave (German: lager) packed in the last ice and snow of the season, to be brought out in October - hence the Oktoberfest festival. (these beers were, and still are, called Märzen Ales, German for "March"). They soon discovered that, not only did this process preserve the beer, but it continued to ferment and "condition", producing a clearer and crisper tasting brew. Thus began the style that we now call the lager. Later, when the role of yeast was better understood, it was discovered that the strains of yeast that survived the lagering process were hardier and when introduced into fresh batches "bottom fermented" and would ferment at a lower temperature than the ale yeast.
Today, most mass-produced beers are lagers. The lagering process allows for greater standardization. What we think of as "beer" is largely shaped by what the large brweries put out. Most small-batch, craft and micro-brews are ales. Brewing an ale allows for more subtle flavor profiles, as the warm fermentation process releases more of the "esters" that give an ale a distinctive flavor. There is also the matter of the lagering process being more time consuming - a small brewer often cannot afford to tie up their equipment for the time required.
Future posts will discuss the many styles and substyles of ales and lagers, as well as hybrids such as Kölsch and Altbier.
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