A special feature of Belgian beer culture are the so-called lambics: Beers that - as used to be common everywhere - are produced by spontaneous fermentation.
In this process, the beer wort is boiled in a kettle for several hours and then stored at room temperature in a well-ventilated room.
The yeast necessary for fermentation catches the beer from the air. Then the drink is bottled in oak or chestnut barrels, where spontaneous fermentation begins.

Several of these beers - Lambic, Gueuze, Kriek, Faro or Framboise - can be sampled at the International Gueuze & Kriek Festival, the Night of Thirst. The festival attracts lambic fans from all over the world to the small Flemish town of Itterbeek.
A marquee serves as a beer hall, and beers from other countries that have also been produced using spontaneous fermentation are served alongside local specialties from Pajottenland.