This study investigated the effect of kernel hardness, processing method, and their interaction on particle size, dry matter (DM) disappearance (DMD), and fermentation characteristics of wheat grain in batch cultures. The study was a completely randomized design with 3 wheat classifications (soft, medium, hard) × 3 processing methods (grinding, dry- and temper-rolling). Fifty-five wheat samples were characterized for chemical traits and classified for kernel hardness. Samples were either ground through 1-mm screen, dry-rolled or temper-rolled to a constant processing index (PI) of 0.80. In vitro gas production (GP) kinetics, fermentation characteristics and DMD at 6, 24 and 48 h of incubation were measured. Crude protein (CP) (g/kg) was lower and starch (g/kg) was higher for soft than medium and hard wheat. The PSD of rolled wheat was affected (P < 0.01) by a wheat hardness × processing interaction. With dry