TECHNOLOGY FOCUS - BIOLOGY - Preferred Method: The pretreating of biomass is carried out with a high shear milling device. The pretreating step is performed on sheared or milled biomass. The method further comprises contacting biomass with at least one cellulase enzyme. The exposure of biomass to cellulase enzymes is at 30-55 degrees C for 24-72 hours. The biomass is exposed to a cocktail of enzymes that convert cellulose into glucose and hemicellulose to xylose and arabinose. The method further comprises grinding the milled grain to a relatively uniform particle size using a colloidal mill prior to exposure to at least one cellulase enzyme; and comminuting the biomass feedstock with a hammer mill prior to pretreating the biomass feedstock with the colloid mill. The making of biofuel step comprises: hydrolyzing a starch to generate sugars; and fermenting sugars to generate biofuels. The fermentation process produces particles in a fluid mash and the colloid mill has gap rotational controls for choosing a gap size. The pretreated particles are used in a fermentation process. The fermentation process further comprises separating the particles from the fluid mash using separation equipment and choosing a gap size to produce particles with a relatively uniform particle size consistent for use with the separation equipment. Preferred Components: The biomass is corn and at least 95% of the pretreated particles have a particle size 100-800 microns, preferably150-300 microns. The cocktail of cellulase enzymes comprises cellulases, xylanases and ligninases. In the fermentation process the biomass is corn and at least 95% of the pretreated particles have a particle size of 150-500 microns.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The high shear milling device is a colloidal mill. EXAMPLE - Corn stover material was ground to a powder by a hammermill. The material was rehydrated to achieve a dry solids weight of corn stover (10%). The material was run through the colloid mill for 25 minutes continuous loop at a gap setting of 0.1-0.15 mm. The material was incubated at 50 degrees C with a cellulase and hemi-cellulase for 24 hours. Then the material was recirculated through the colloid mill which produced approximately 10% more sugars, which were used to produce biofuels.