The Omnivore's Dilemma - Michael Pollan [45]
About a fifth of the corn river flowing out from the elevators at the Iowa Farmers Cooperative travels to a wet milling plant, usually by train. There it diverges into a great many slender branching tributaries, only to converge much later on a plate or in a cup. For what the wet mill does to a bushel of corn is to turn it into the building blocks from which companies like General Mills, McDonald’s, and Coca-Cola assemble our processed foods.
The first rough breakdown of all that corn begins with the subdivision of the kernel itself: Its yellow skin will be processed into various vitamins and nutritional supplements; the tiny germ (the dark part nearest the cob, which holds the embryo of the potential future corn plant) will be crushed for its oil; and the biggest part, the endosperm, will be plundered for its rich cache of complex carbohydrates.
This oversized packet of starch is corn’s most important contribution to the industrial food chain: an abundance of carbohydrate molecules in long chains that chemists have learned to break down and then rearrange into hundreds of different organic compounds—acids, sugars, starches, and alcohols. The names of many of these compounds will be familiar to anyone who’s studied the ingredient label on a package of processed food: citric and lactic acid; glucose, fructose, and maltodextrin; ethanol (for alcoholic beverages as well as cars), sorbitol, mannitol, and xanthan gum; modified and unmodified starches; as well as dextrins and cyclodextrins and MSG, to name only a few.
To watch the stream of corn coming off of George Naylor’s farm proceed to divide, subdivide, and ultimately branch off into a molecule of fructose destined to sweeten a soda is not as easy as following it to a feedlot into a cut of meat. For one thing, the two companies who wet mill most of America’s corn (Cargill and ADM) declined to let me watch them do it. For another, the process is largely invisible, since it takes place inside a series of sealed vats, pipes, fermentation tanks, and filters. Even so, I would have liked to follow my bushel of corn through ADM’s plant in Decatur, Illinois (the unofficial capital of corn processing in America), or to Cargill’s mill in Iowa City (the likely destination of the train I saw being loaded at the elevator in Farnhamville), but the industrial food chain goes underground, in effect, as it passes through these factories on its path to our plates.
The closest I got to following corn through a mill was at the Center for Crops Utilization Research at Iowa State University, in Ames, forty-five miles from the farmers cooperative elevator in Farnhamville. After my visit to George Naylor’s farm, I spent a couple of days on the Ames campus, which really should be called the University of Corn. Corn is the hero of the most prominent sculptures and murals on campus, and the work of the institution is dedicated in large part to the genetics, culture, history, and uses of this plant, though the soybean, Iowa’s second crop, gets its share of attention too. The Center for Crops Utilization Research is charged with developing new uses for America’s corn and soybean surplus, and to this end operates a scaled-down wet milling operation, a Rube Goldberg contraption of stainless steel tubes, pipes, valves, vents, drying tables, centrifuges, filters, and tanks that Larry Johnson, the center’s director, was more than happy to show me.
To hear Johnson describe it, the wet milling process is essentially an industrial