Spontaneous Fermentation Beer
In spontaneous fermentation the brewer does not inoculate the hopped, lambic wort with a yeast culture. Instead, the hopped wort is exposed to the cool outside air, which results in spontaneous fermentation. Although these beers can theoretically be brewed anywhere, the most suitable microflora are found in the air to the south west of Brussels, in the region known as the ‘Zennevallei’ and ‘Pajottenland’.
Lambic is a flat, sour wheat beer which fermented with airborne yeast and aged on wooden barrels. Traditionally, young and old lambic are blended with each other and then re-fermented in the bottle to obtain a sparkling geuze beer.
Oude geuze (5 - 7 vol.%) is a blend of spontaneously fermented lambic beers of different ages, the oldest being at least 3 years old and the average at least 1 year old, and refermented in the bottle. Only this type of beer can be called “oude geuze”, this being protected as “guaranteed traditional specialty” on a European level.
Geuze is usually a more commercial variant, either not consisting of a blend of 1, 2 and 3 year old lambic, or being a blend of spontaneously fermented beer with a top-fermented beer. The adjective “oud” or “oude” may not be used in this case.
Faro is a sweetened low-alcohol beer made from a blend of lambic and a much lighter, freshly brewed beer to which brown sugar (or sometimes caramel or molasses) was added. The use of the lighter beer (or even water) and of substandard lambic in the blend made this a cheap, light, sweet beer for everyday use. The sugar was originally added shortly before serving, and therefore did not add carbonation or alcohol to the beverage and gave it a sweet taste.
Oude Kriek is the most traditional fruit beer and is brewed using 100% lambic as a base. Cherries are macerated in lambic to obtain this beer (e.g. Mort Subite, Boon, Lindemans, Timmermans, De Troch, Cantillon, Drie Fonteinen, De Cam, etc.). The name is protected by on a European level, like Oude Geuze.