Modeling the Energy Requirements of Firstbreak Grinding

The influence of roller mill gap and single kernel properties of wheat on the energy requirements of firstbreakgrinding was studied. Multiple linear regression models for energy per unit mass (EM), new specific surface area (ANSS, inlog scale), and specific energy (EA = EM /ANSS) were developed based on milling data from six wheat classes ground at fiveroll gaps with an experimental roller mill. The models, which were functions of roll gap, single kernel properties, and wheatclass as a classification variable, explained most of the variability in the experimental data. Roll gap and single kernelhardness had the greatest influence on EM, ANSS, and EA. Milling ratio, a variable that combined single kernel size and rollgap, reduced some collinearities among single kernel properties and isolated the effect of single kernel mass from that of singlekernel size. The effect of single kernel mass became significant in the models based on milling ratio. Good agreement betweenpredicted and measured values was observed from 100 validation samples. The EA model is a potential alternative to breakrelease as a basis for online roll gap control.