What are Lagers and Ales?

As an extension to this post, I’m going to try to document characteristics of each type of beer. This is mostly for my own benefit, as I try to study for this blasted certification course, but I figured this is as good of a place as any to get any feed back.

But before I can get into the specifics of each kind of beer, it’s probably best to lay out the bigger picture here. Yes there are dozens of different varieties of beer out there, perhaps even hundreds. But these beers fall into only one of two categories: Lagers and Ales. What differentiates these two categories? The yeast used for fermentation.

Lagers use what is called a bottom-fermenting yeast. Ales use a top-fermenting yeast. Think of the difference this way – When the wort is fermenting, a lager ferments on the bottom of the fermenting vessel. An ale ferments near or at the top of the fermenting vessel. There are many strains of bottom-fermenting yeasts and many strains of top-fermenting yeasts.

(There’s actually a third style of yeast, mostly used in Belgium, that creates what is known as ‘spontaneous fermentation’, that’s sort of a weird beast. I will cover that in a later post).

The choice of yeast depends on a variety of influences a brewer must take into account. Certainly for must of us would take taste into consideration, but for mass production of beer, cost must also be a concern.

Fermenting itself does three things of varying efficiency (meaning that it’s dependent upon which strain of yeast one chooses). Converting sugars to alcohol is one of the primary functions, but so is the creation of carbon dioxide (the fizziness), as well as adding flavor components.

Now as near as I can figure, the bottom-fermenting yeasts carry about them a feature which makes them very attractive to large-scale brewers, namely that they are very efficient in fermenting sugars. Sure it may take longer to do so (many lagers do require a longer fermentation period than ales), but it also means less sugars left in the final product. With less sugars in a product, the longer shelf-life the beer has, which in turn means that the lager can hold value for a longer period of time than an ale.

But the sugars also mean a other differences as well, affecting everything from taste to even opacity. I’ll refrain from stating whether a lager is better than an ale, or vice versa, because that isn’t the point. The point is that when one drinks an ale, one should have expectations a that are different from when one drinks an ale. A lager, typically, is crisper and has a taste that is likely to be a little dry (I’m using dry here much in the same way a wine drinker would). An ale, by comparison, will be a little more full bodied in taste, and have more flavors affected by the remaining sugars in the beer.

Now that’s not to say that these standards are universally true, because one must also take into account things such as grain composition, types of hops used, length of time hops are used, aging techniques, etc, etc. Heck, even serving temperature isn’t dependent upon whether it’s a lager or ale. Dopplebocks, as an example, is a lager which has a suggested serving temperature higher than that of pale ales and porters.

So, when I speak of lagers, think of a beer made with a bottom-fermenting yeast that may result in a crisper, drier, beer. And when I speak of ales, think of a beer made with a top-fermenting yeast that may result in a fuller-bodied beer. I’ll endeavor to point out when deviations from this statement occur.