Beer basics – Ales and lagers
The variety of beers available at a bar or liquor store can be overwhelming – row after row of different styles. Don't be deceived by the number of options, though. In the end, there are really only two styles of beer – ales and lagers. They're separated not by color or flavor, but instead by the type and behavior of the yeast used in the brewing process.
The majority of mass market beers in the United States are lagers. Lagers are 'bottom fermented' – just like it sounds, the yeast gathers or sinks to the bottom during the fermentation process. These yeasts work slowly and at low temperatures, around 34 degrees. The brewing process takes longer, but comes with a benefit for commercial brewers – extremely consistent flavor from batch to batch.
Ales, now, there's another story. Ales are 'top fermented,' so the yeast floats along the surface of the beer. These yeasts need higher temperatures to work, generally anywhere from 60 to 75 degrees. In turn, they need much less time to work, sometimes as little as a week.
At first glance, it would seem logical for a mass market brewer to prefer ales to lagers. After all, you'd think the faster turn-around time would be a plus. That speedy yeast also comes with what can be seen as a down side – these top-fermented yeasts produce more of a by-product called esters.
Like many things, those esters can be either good or bad, depending on your point of view. For brands like Budweiser, Coors, or Michelob, which need to produce large quantities of beer with absolutely no taste variations, the strains of yeasts uses in lagers are far easier to work with. Their predictability outweighs any benefit that would be gained from faster production. Lagers generally have a relatively limited range of flavors – hoppy or malty, sweet or dry. This goes a long way towards explaining why many people that think all beers taste alike – basic lagers do taste very similar. They're supposed to.
But esters can create an amazing variety of flavors in a beer. The most common flavors are described as flowery or fruity, like apple, pear, or grass, but it's possible to brew ales with flavors of cloves, vanilla, or butterscotch. These aren't flavored beers, they're brews that take advantage of a side-effect of the brewing process. The yeasts are more difficulty to control, and getting consistent results is more difficult, but the flavor options are almost limitless.