The brewing of beer is a rich and varied subject. And if you have ever been overwhelmed by a beer menu, you know that there are many different types of beer. A fundamental difference is the division between the two main varieties – ale and lager.
There is a significant history behind the rise of each type; however, to keep this simple, we will cut right to the chase – after all, you need to get yourself a beer soon, right?
Only one element is always different to distinguish an ale from a lager.
Yeast. Each type is brewed with a different species of yeast.
Ales are brewed with Saccharomyces cerevisiae strains, a top-fermenting yeast that operates at warmer temperatures (around 55-77°F). Lagers are made using strains of Saccharomyces pastorianus, a bottom-fermenting strain of yeast held at a colder temperature (about 40-52°F).
Since the beers are brewed using yeast from two different species, it’s reasonable to expect them to behave differently and have other properties.
Ale is not a style of beer, nor is lager. The next time you peruse a beer menu, judge the beer on its merits not on the variety. And most importantly, if you like it, that's all that matters.