Corn refiners use #2 yellow dent corn, which is removed from the cob during harvesting. An average bushel of yellow dent corn weighs 56 pounds. Approximately 70 percent of the kernel is starch (from the endosperm), about 10 percent is protein (predominantly gluten), four percent is oil (extracted from the germ), and two percent is fiber (from the hull).  It is the goal of the corn refining process to separate each component and then further refine it into specific products.

Corn arrives at the refining facility by truck, barge or railcar. Refinery staff inspect arriving corn shipments and clean them twice to remove pieces of cob, dust, chaff, and foreign materials. The corn is then conveyed to storage silos, holding up to 350,000 bushels, until ready to go to the refinery for steeping, the first processing step.