If you want to categorize beer (and really, who doesn’t?), one of the better places to start is determine the fermentation styles. Ale uses a top-fermenting brewer’s yeast. Lager uses a bottom-fermenting yeast. And lambics? Well, they require a bit of explanation.
Where lagers and ales have yeasts intentionally added to their wort. These yeasts can best be described as being domesticated, created specific for the use of brewing.
Lambics go about getting their yeast by throwing caution to the wind. The wort is exposed to the wild yeasts of Belgium, sometimes doing nothing more than opening the windows of their breweries in order to let the yeasts from the outside come in and settle upon their brew. Then fermentation begins.
Being wild yeast, their fermentation is less efficient than those found from domesticated yeasts. As such, many more sugars and esters are found in lambics. This is the reason that many lambics are sweeter and tarter than ales and lagers.
Lambics are also odd in their use of unmalted wheat used in conjecture with the standard malted barley.
These are the reasons that lambics are quite possibly the oldest beer recipes still in use today. Open air fermentation plus unmalted wheat results in something quite different from the golden and amber ales we’re used to seeing.
I’m going to see if I can explore lambics for a bit. It’s not as big of a world as, say, lagers, so the time spend should be short. But it will very likely be interesting.