Petrus Roodbruin is a blend of 33% Petrus Aged Pale, pure cask beer that matures for 2 years in oak barrels, and 67% young brown beer. In this blend, the young dark beer provides the red-brown color and the Aged Pale for the mildly sour taste. Petrus Roodbruin is a typical Flemish reddish-brown beer as tradition requires.