Lambic

Lambic is a Belgian beer style that relies on spontaneous fermentation with native wild yeasts and bacteria rather than selected brewing yeasts. It is traditionally produced in the Pajottenland region, to the southwest of Brussels, and in the surrounding Brussels area. The wort is made from a mix of malted barley and a high proportion of unmalted wheat, and it is boiled with aged hops to help preserve the beer and mellow bitterness. After cooling, the wort is transferred to open wooden vessels where airborne microflora inoculate the brew.

Fermentation and aging occur in these wooden vessels, often for one to three years. Lactic acid bacteria develop acidity, producing sour flavors, while Brettanomyces yeasts contribute distinctive funky, earthy, and fruity notes. The long, spontaneous maturation gives lambic its characteristic complexity and dryness. Unblended lambic typically finishes with a moderate to low ABV, roughly 5–8% depending on the batch.

Because of its unconventional fermentation, lambic is frequently used as a base for blends and fruit beers. Gueuze is made by blending young and old lambics and allowing a second fermentation in the bottle. Kriek (cherries) and Framboise (raspberries) are popular fruit lambics created by adding fruit to the beer, often during aging. Oude Gueuze refers to blends of aged lambic that have undergone extended maturation.

Modern lambics are produced by a number of Belgian breweries known for traditional methods, including Cantillon, Drie Fonteinen, Boon, and Oud Beersel, among others. The style remains closely associated with the specific terroir of the Brussels and Pajottenland region.