Kriek is a style of Belgian beer, made by fermenting lambic with sour Morello cherries. The name is derived from the Flemish word for this type of cherry (kriek). Traditionally "Schaarbeekse krieken" (a rare Belgian Morello variety) from the area around Brussels are used. As the Schaarbeek type cherries have become more difficult to find, some brewers have replaced these (partly or completely) with other varieties of sour cherries, sometimes imported. Kriek have been described as the "pink champagnes of the beer world."
Traditionally, kriek is made by breweries in and around Brussels using lambic beer to which sour cherries (with the pits) are added. The presence of cherries predates the almost universal use of hops as a flavoring in beer. A traditional kriek made from a lambic base beer is sour and dry as well. The cherries are left in for a period of several months, causing a refermentation of the additional sugar. Typically no sugar will be left so there will be a fruit flavour without sweetness. There will be a further maturation process after the cherries are removed. Lambic that undergoes a second fermentation in the presence of sour cherries before bottling results in kriek, a beer closely related to Geuze.