Classic Sour Beer Styles
There are a handful of beer styles brewed today where sourness, with or without the influence of wild yeast and wood, is an expected and welcome part of the beer’s profile.
Lambic: These wild-fermented beers from the Pajottenland region southwest of Brussels are the oldest beer style still made. The brewing process is archaic: When the wort (the sweet liquid precursor of beer) is ready, it is exposed to the open air to be colonized by ambient wild yeast and bacteria. This sounds haphazard, but it is anything but— unable to control the organisms that settle in the beer, the lambic brewers instead manage the conditions in which the beer ferments and matures. According to Jeff Swallow, the airborne organisms probably aren’t sufficient to get fermentation going. The secret is to move the inoculated wort to barrels that contain reliable communities of organisms. After one to three years, a master blender combines lambics of various ages—a step that is repeated in many other wild and multi-organism beer styles—to create a final beverage that is layered, complex and challenging.
West Flanders Sour Red Ale: These brilliant, tart beers also rely on the perpetuation of bacterial colonies in wooden vessels to add lactic and acetic (vinegar) notes to the aging beer, as well as related esters. At renowned Rodenbach, brewmaster Rudi Ghequire defines the acidification of the beer as “a late Middle Ages conservation method” that prevented spoilage by pushing pH levels too low for dangerous bacteria to thrive, as older, more acidic beer was mixed with younger batches. Foeders, the giant oaken tuns where the beer matures, vary enough from one to another that several different foeders are tapped for the final blend.
East Flanders Brown Ale/Oud Bruin: In East Flanders, the region’s sour beer is based on a brown ale, with more caramel, toffee and dark fruit notes than the red beers of its western neighbor. The oud bruin (old brown) beers are matured in stainless steel, a more controllable medium than wood. One notable example of oud bruin, Liefmanns Goudenband, is an almost purely lactic beer, with little acetic or wild character. The final beer has a rich, malty character, almost sherry-like.
White Ale/Wit Beer: This spicy Belgian wheat ale was once one of many similar beers found across Belgium and into England. It teetered on the edge of extinction early in the 20th century, and was revived in large part by Pierre Celis, who brought the style to the United States. Randy Mosher recalls, “Pierre Celis was pretty generous with details about his beer, but I understand he had a locked room in the brewery in Texas where only he had the key, and he did some sort of lactic fermentation in there. It’s a minor detail, but it’s an important part of the overall flavor profile of those white beers to have a kind of a bright, palate-cleansing acidity that helps balance the creamy, milkshaky texture.”
Berlinner Weisse: Napoleon dubbed this cleanly acidic wheat beer “the Champagne of the North.” Mosher, again: “That’s a lactic fermentation. Historically, those beers were made from unboiled wort. If you’ve ever smelled spent grain or grain out in the field, that stuff has a huge amount of lactic and Pediococcus bacteria living on it naturally.” Other, rarer north German beers, such Lichtenhainer and Leipziger Gose, also display some lactic acidity, either from bacteria or from the acidification of the malted grain.
