For most people, “beer” means only one thing: a straw-colored, highly carbonated, mildly flavored drink—the sort of beverage that is served in response to the request “Just give me a beer.” But more and more beer drinkers realize that there are many styles of beer, each with its own characteristics, occasions and story to tell.
Ale and lager are both beers fermented from grain. The major difference between these two beer families stems from the temperature at which fermentation is carried out. And the importance of these differences in temperature is that chemical reactions happen more slowly at lower temperatures. Brewers generally want their beer to attenuate (convert sugar to alcohol) slowly in the ferment, thus changes will take place over a longer period of time.
Lager is a type of beer. All beer is either a lager or ale. Ale is brewed with top-fermenting yeast (Saccharomyces cerevisiae) and lager with bottom-fermenting yeast (Saccharomyces uvarum)
Although wheat, rye, oats, millet, sorghum, rice and corn have all been used for brewing, barley is the preferred grain for beer. But the starch in a grain of barley isn’t ready to be fermented into alcohol, so the barley is generally converted into malted barley, or “malt.” The process of malting involves soaking the barley, allowing it to germinate, and then stopping germination with heat. Thanks to malt, lagers and ales both come in a full range of colors, strengths, and characters.