What makes Lambic beer special?
Lambic is a beer made with at least 30% unmalted wheat and by spontaneous fermentation, meaning that the brewer does not pitch yeast into the wort. The wild yeast and bacteria come from the air and environment. Dirk Lindemans explains that “the microflora in the air depends on the type of soil, microclimate and vegetation. These wild yeasts are everywhere, but in Pajottenland and the Senne Valley the ratios and concentrations are completely different, producing that specific Lambic taste.” Because these wild yeasts mustn’t be too abundant, Lambic is brewed only in the colder months of the year, making it one of the few remaining truly seasonal beers. The wort is cooled overnight in open shallow tanks (coolships) allowing the wild yeasts and bacteria to submerge themself. It is also common to use ‘old’ hops for preservation purposes, which is why these beers rarely have any hop flavors or aromas. It is thought that this beer style dates back to at least the Middle Ages (if not before), though verified written accounts don’t describe it specifically until later, for example the Ordonnance of 1560. A copy is proudly hanging on a wall at Oud Beersel.
Lambic is aged in oak or chestnut barrels for a period of one up to three years resulting in a flat beer, because the carbon dioxide has escaped through the wood. The barrels used for maturation come in different sizes, the largest of these are ‘foeders’ and can hold up to 10.000 liters. When bottling different blends of Lambic based on the méthode champenoise, it further ferments in the bottle resulting in a sparkling version called Geuze, which is always a blend of young (1 yr) and older Lambics (2 and 3 yrs). Since 1997, Lambic, Geuze, Oude Geuze, Kriek (with cherries) are protected names under European law, which distinguishes lambic and geuze beers according to the raw materials used and the traditional brewing process.
