Corn Refining

Corn refining is a two-step process that involves the wet milling and processing of corn. Shelled yellow dent corn, which has been removed from the cob during harvesting, is cleaned and steeped (softened) in tanks with a water-based solution, releasing starch. Steepwater is drawn off and corn is milled, breaking the germ loose. Steepwater is then used in animal feed and to support fermentation of other products.

Mechanical and solvent processes during germ separation extract oil from the germ. The corn leaves the germ separator in a water suspension for further grinding to release starch and gluten from the kernel fiber. The starch and gluten slurry is piped to starch separators. The fiber and germ residue (spent flake) are sold as animal feed.

Gluten (corn protein), lower in density than starch, is removed from the starch in a centrifuge. The extracted gluten meal is used as poultry feed and in pet food. Starch is collected and washed to produce a high-quality starch. Starch is either dried and then marketed, modified into specialty starches or converted into corn syrups and other sweeteners.