Sour beer is a type of beer that has a tart, tangy flavor, which is achieved through specific fermentation processes. This style often uses wild yeast strains, such as Brettanomyces, and bacteria like Lactobacillus or Pediococcus. These microorganisms produce lactic acid, giving the beer its characteristic sourness. Common styles of sour beer include Berliner Weisse, Gose, and Lambic. Sour beers can be enjoyed on their own or paired with food, as their acidity can complement various dishes. The growing popularity of sour beer has led to many craft breweries experimenting with different ingredients and aging techniques.