Effects of Tempering Moisture and Roll Differential on Wheat Size Reduction Process during the First Break Rollers

Abstract

<abstract><title><italic>Abstract.</italic></title> In this study, the effects of tempering moisture and roller differential on the size reduction process of soft white winter (SWW) wheat during the first break rollers were investigated. The experiments were carried out according to a completely randomized factorial arrangement of six tempering moistures of 9.3%, 11.3%, 13.3%, 15.5%, 16.5%, and 18.1% dry basis (d.b.) for four roller differentials of 2.5:1, 3.0:1, 3.5:1, and 4.0:1 with duplicate tests. The tempering moisture and roller differential affected particle size distribution (p < 0.01). Since bran was difficult to break at higher tempering moisture levels, the amount of particles with sizes >1180 μm increased with an increase in tempering moisture and at higher roller differentials, and longer shear and compressive stresses on wheat generated more fine particles. It was also observed that the effect of roller differential increased with an increase in tempering moisture.