One of the first decisions that a brewer must make about any given batch of beer is whether they are creating a batch of ale or lager. Most beginner brewers are going to opt for an ale because the process is a lot simpler, you need less equipment, and the styles of beer often allow more elbow room for mistakes. However, many of us novice brewers have not been exposed to a lot of craft beer styles, so we might not be familiar with too many kinds of ales. I was convinced I brewed my first beer wrong until I tasted a commercial style and found out that I just had no idea what I was supposed to be tasting.
Lager and ale are the most general categorizations of beer, and most, if not all, beer falls into one of these two styles (the status of hybrid styles is a matter of debate). However, both types of beer consist of many different variations, so much so that it is difficult to make any generalizations about either group. At the end of the day, there is a considerable amount of overlap between the two styles, and the only consistent differences between the two are related to brewing approach and fermentation strategies.
From a general perspective, ales tend to be more robust beers than lagers, tend to have a higher level of complexity and are more often aromatic and fruity than lagers. A great example of this is the first beer that I brewed, an English Brown Ale, which typically contains a lot of fruity esthers. Additionally, there are more bitter ales than there are bitter lagers. Ever heard of an IPA? Yeah, it's an India Pale Ale. Ales also tend to be served warmer than lagers. Porters, stouts, IPAs (all categories), pale/red/brown ales (obviously), weizens (wheat beers), witbiers, and even sour beers are considered ales.
In contrast, lagers include lighter-tasting beers, which are often mellow and smooth. The taste and aroma of these beers tends to be more balanced and subtle, and served icy cold! Budweiser and Coors are both American style lagers. Heineken? Lager. Pilsner Urquell? Lager. Dos Equis, Tsign Dao and just about any famous, internationally known beer is going to be a Lager. Even Sam Adams, the largest “craft brewery” in the US has a lager as a Flagship beer. Not all lagers are plain and fizzy though – there are many styles of lagers that can be complex, high gravity, and of course interesting craft beers!
Bocks, dopplebocks, oktoberfests, maibocks, Eisbocks (lots of german stuff here), and various helles style beers are all considered bocks. They are still crisp, clean beers, but are slightly more interesting that the more infamous lagers listed above.
However, the overlap between these different styles are so significant that characterizing beer on its taste alone is very difficult for a beginner. For more experienced brewers and craft beer enthusiasts, you may be able to pick up on some lager yeast characteristics like sulfur.
Types of yeast for fermentation fall into two types, either ale or lager yeast. The differences in fermentation between the two styles are largely related to differences in fermentation temperatures.
The yeast that is used for brewing ales are also known as top brewing yeast, because when the yeast is active it is at the top of the mixture, and is warmer overall. In contrast, the yeast used for brewing lager is active at the bottom of the mixture and uses lower temperatures. Ales can ferment for about 2 weeks at 65-68 degrees and be ready to bottle. Lagers take significantly longer, and require some special equipment unless you have some widely varying temperatures in and around your house. Typically you'll want to ferment at about 50 degrees for 2 weeks, lager at 40 degrees for about 4 weeks (lagering basically means to let the beer ferment slowly at a lower temperature), then bring it up to about 60 degrees for 2-3 days before bottling or kegging. Those last couple days at higher temps are meant to allow the yeast to completely ferment out the beer, preventing any excess diacetyl that may still be left in the wort.
PS, don't quote me on those temps and times, they are approximations. I recommend you find a recipe specific to your beer, and see what the experts have to say before getting started on your first lager. Mine was a chocolate bock, which didn't turn out fantastic. It's still aging in the bottle and I'm hoping some of those off flavors dissipate with time.
There is some confusion about the names of the yeast strains used to ferment lager and ale, because these names have changed over the years. Initially, the yeast used for lager was referred to as Saccharomyces pastorianus, while the yeast for ales was known as Saccharomyces cerevisiae. However, a second species of lager yeast is sometimes described as Saccharomyces carlsbergensis. Scientific examination has since revealed that the two strains of lager yeast are the same, and they are now referred to as Saccharomyces pastorianus, as this is the oldest of the two names.
Hybrid styles of beer are beginning to be popular in the market and among brewers. As their name suggests, these beers represent a middle-ground between ales and lagers. However, many brewers contest this categorization, arguing that all beer can be categorized by the type of yeast used, making the hybrid category redundant.
Regardless of how they are classified, hybrid beers are unique because they make use of the yeast from one type of beer, but the brewing technique from the other type of beer. For example, brewing lager requires refrigeration during one part of the process, but some hybrid beers use lager yeast, and ale techniques, meaning that refrigeration is not needed.
Some examples of hybrid beer include California Common (or steam beer), Kolsch and Altbier. The category remains relatively small, and most beer styles fit neatly into the categories of ale and lager. The most famous California common you know is Anchor Steam. They've got a copyright on “steam beer”, so breweries looking to imitate the style use the alternate name instead. Kölsch beers are very similar to Port wines and Champagne, in that you can only call beers from the specific region of Kölsch under that name. Craft breweries now have to make brews labeled as “Kölsch style beers”. Both these styles use ale yeast strains at cooler temps. Never heard of altbiers? My favorite is from Hangar24!
Which To Brew?
Personally, I've had much more success with ales that lagers so far. And considering that you'll need less equipment for temperature control (fridge for summer, varying warm spaces for winter), I'd recommend starting with an ale. My first was a brown ale, but I read that they are quite forgiving for mistakes. Mine turned out OK despite numerous screw ups on my part. IPAs are also nice to start with because the ample use of hops can hide many off flavors. An ale basically takes 2 weeks at a constant temperature, while a lager can take 1-2 months at 3 different temperatures. Ever time you move the beer, that's another chance for aeration or infection, so an ale will greatly reduce your chance to make a newbie mistake that could ruin your beer!
Which do you prefer to brew?