Contact: Mark Lindley
Director, Corporate Communications
The Corn Wet Milling Process
Corn is converted into various products including sweeteners,starch and corn oil. The corn-refining process begins with shelled yellow dent corn which has been removed from the cob during harvesting.
1. INSPECTION AND CLEANING
Refinery staff inspectarriving corn shipments and clean them twice to remove cob, dust, chaff and foreign materials before steeping. Corn refining has been the fastest growing market for U.S. agriculture over the past twentyyears, and refiners now use around 16% of the $21 billion U.S. corn crop. Since a large amount of the nations' corn production never leaves the farm on which it was produced, corn refining is a vitalfactor in the cash market for U.S. corn. Each day the production of about 35 thousand acres of corn arrives at corn refining facilities before conversion to food, industrial and feed products.
Each stainless steel steep tank holds about 3,000 bushels of corn for 30 to 40 hours soaking in 50 degree Celsius water. During steeping, the kernels absorb water, increasing their moisturelevels from 15 percent to 45 percent and more than doubling in size. The addition of 0.1 percent sulfur dioxide to the water prevents excessive bacterial growth in the warm environment. As the corn swellsand softens, the mild acidity of the steepwater begins to loosen the gluten bonds within the corn and release the starch. After steeping, the corn is coarsely ground to break the germ loose fromother components. Steepwater is condensed to capture nutrients in the water for use in animal feeds and for a nutrient for later fermentation processes. The ground corn, in a water slurry, flows to thegerm separators.
Corn Products International, Inc.
3. GERM SEPARATION
Cyclone separators spin the low density corn germ out of the slurry. The germ, which contains about 85% of the...