Traditionally, kriek is made by breweries in and around Brussels using lambic beer to which sour cherries (with the pits) are added.[2] A lambic is a sour and dry Belgian beer, fermented spontaneously with airborne yeast said to be native to Brussels; the presence of cherries (or raspberries) predates the almost universal use of hops as a flavoring in beer.[3] 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.