Abstract: A method and apparatus are disclosed for liquefaction of starch derived from cereal grain. A single-screw extruder is utilized to gelatinize a starch substrate providing significant advantage over prior art jet steam cookers. Liquefaction of the gelatinized starch substrate is completed by post-extrusion bioreaction of the starch with a static-mixer reactor. An alpha-amylase enzyme is utilized to facilitate the liquefaction process. The Liquefacted starch substrate is heated after bioreaction to achieve complete digestion of remaining starch inclusions. Liquefacted starch substrates utilizing the disclosed process significantly reduce the amount of energy required in the conversion of starch to fermentable sugars in the production of ethanol.