surøl

Suröl is a term used in some Scandinavian languages to refer to sour beer, a beer whose acidity and tart character are produced intentionally through microbial activity during fermentation and/or maturation. The sour profile often results from lactic acid bacteria, such as Lactobacillus or Pediococcus, sometimes in combination with wild yeasts like Brettanomyces, and can be complemented by acetic acid production and complex, fruity or funky aromas.

Production methods vary. Kettle souring is a common, controlled technique where lactic acid bacteria are introduced into the wort before boiling, creating acidity quickly; after souring, the wort is boiled to kill the bacteria and then fermented with conventional yeast. Mixed fermentation uses a broader set of microbes, typically in wooden or neutral vessels, and often involves long aging in oak barrels to develop complexity. Spontaneous fermentation relies on ambient environmental yeasts and bacteria to inoculate the beer, a traditional Belgian approach that can yield highly complex profiles. Some German styles, such as Berliner Weisse and Gose, are naturally sour through lactic fermentation, sometimes with salt or coriander in Gose.

Notable styles and traditions include Belgian lambics and related beers (Gueuze, Kriek, Framboise), German Berliner Weisse and Gose, and a wide range of modern craft beers that blend souring with fruit, hops, or other flavorings. Suröl has gained global popularity through the craft beer movement, with producers worldwide experimenting with accessibly tart pale ales to intensely funky, barrel-aged blends.