Beers of mixed fermentation
Various yeast cultures are used for beers of mixed fermentation. Usually the parent brew is a top-fermenting beer and a part of this is stored in oak barrels for one and a half years or longer. A lactic acid fermentation process takes place during this time and this beer is then mixed with young, high fermentation beer.
Versnijbier (6 - 8 vol.%)
Versnijbier or blended beer, is brewed by blending old and young beer or mixing beers of spontaneous fermentation with high and low fermentation beers (e.g. Petrus Aged Pale, Cuvée Watou, Vicardin Tripel Geuze, etc.). The most traditional type of this blended beer is the so-called ‘oud bruin’.
Vlaams Bruin / Flemish Brown (4,5 – 8 vol.%)
Vlaams Bruin is associated with the region around Oudenaarde. These are beers with a deliberate lactic acid infection and often slightly sweetish. They are obtained by mixing young beer and “old” beer aged on metal tanks or wooden barrels.
Flemish red-brown beer (5 - 6,5 vol.%) is brewed with reddish barley malts and is associated with southern West Flanders. They are obtained by mixing young beer and “old” beer aged on wooden barrels. The beers tend to be spicy instead of bitter and have a distinctive, crisp, slightly citrussy note (e.g. Rodenbach, Duchesse de Bourgogne, Vander Ghinste Oud Bruin, etc.).
'Oud Bruin' / Flemish Sour Ale’
'Oud Bruin' / Flemish Sour Ale’ is collective noun for Flemish Brown and Flemish red-brown beers.