Lambic beer is an unusual traditional Belgian beer which is produced through spontaneous fermentation, rather than through the careful introduction of specific yeasts and other organisms to malted grains. As a result, lambic beer has a very distinctive flavor, and the flavor of such beers can be rather unpredictable, with each batch being entirely unique. Many lambic producers actually blend their beers, combining young lambics with more mellowed older lambics.
This beer originated on Belgian farms, where workers wanted to be able to quickly brew basic beers without a great deal of fuss. Beer was the drink of choice for laborers well through the 1800s, thanks to the fact that water was often not very potable. As a result, a wide variety of brewing techniques emerged to satisfy an epic taste for beer among European laborers.
Even beer fans are often not very knowledgeable about lambic beer. Fortunately, the tradition of this beer has been retained in the Pajottenland area of Belgium, where this beer has been made since the 1400s, and a growing interest around the world in traditional brewing processes has elevated interest in lambic beer, which is typically sold in the form of a gueuze, a blend of one year old and two to three year old lambics.
To make lambic beer, brewers malt wheat and barley together, typically in a 1:2 part blend. After malting, the grains are cooked into a mash and then exposed to the air. The mash collects wild yeasts from the brewery, and these yeasts trigger the fermentation process. In ancient breweries, the same yeasts contribute to batch after batch, thanks to the fact that they are amply present in the air. The beer may be fermented for an extended period of time before being put in new barrels to mature for up to three years.
Lambic beer is dry, acidic, and often very sour, with a complex series of flavors created through the fermentation process. Most lambics are traditionally blended with hops, which act as a preservative, adding a bitter note to the beer, and some are fermented with fruit for a sweeter note. Lambic beer also tends to be a bit weaker than other beers, depending on the production techniques used.
This beer is a seasonal delicacy, produced only during the winter and spring, because the fall and summer weather is warm enough for potentially harmful organisms to flourish, and these organisms could damage the beer. By tradition, lambic is fermented in the summer months and poured off for maturation in the fall.