An adjustable chaffer assembly is operable to be mounted in a chaffer housing of a harvester. The adjustable chaffer assembly includes forward and aft chaffer sections. The forward chaffer section includes a forward frame assembly and adjustable forward louvers shiftably mounted on the forward frame assembly. The aft chaffer section includes an aft frame assembly and adjustable aft louvers shiftably mounted on the aft frame assembly. The aft chaffer section is shiftably mounted relative to the forward chaffer section and is shiftable between a parallel condition where the frame assemblies are substantially parallel with each other and an oblique condition where the frame assemblies define an oblique angle.