One of the familiar and beloved venues at the Minnesota State Fair is the corn roast, where hungry hordes brandish and eagerly consume nearly 200,000 butter-slathered ears of bicolor sweet corn each year.

The corn comes from a field near Monticello, an hour's drive northwest of the Twin Cities, where grower Jerry Untiedt takes great pains to assure that the corn is harvested fresh daily, and at the peak of its flavor.

"Planting corn in May or June and trying to hit a 12-day window at the fair is kind of like shooting at a ­moving target," he said.

Minnesota is the No. 1 producer of sweet corn in the country, and guaranteed prices from processors help farmers offset volatility in the markets for other crops. In terms of pounds per person, sweet corn ranks fourth as the most consumed vegetable in the nation, according to federal estimates, and what is grown in Minnesota shows up in grocery aisles and ­freezers throughout the year.

Untiedt, whose farms grow dozens of vegetable crops, said the corn roast stand at the fair, run by Brad Ribar, needs about two acres of corn per day on average. That represents a small portion of the 300 acres of sweet corn that he grows and sells at a string of roadside stands and to high-end ­grocery chains in the Twin Cities.

Sweet corn is different from field corn, which is about 98 percent of what Minnesotans see when driving through farm country. Last year, the state produced about $4.9 billion worth of field corn, which matures and dries in the field before harvest and is used for livestock feed, ethanol and in thousands of products.

By contrast, sweet corn is perishable and loses much of its flavor if not consumed, canned or frozen within a few days of harvest.

Minnesota produces nearly one-third of the nation's sweet corn for processing, followed by Washington and Wisconsin. The 2012 Census of Agriculture estimated that sweet corn processed in Minnesota had a value of more than $73 million.

The census also estimated that of the nearly 107,000 acres of sweet corn harvested in the state that year, only about 4,000 acres went to fresh markets, and the vast majority — 96 percent — went to processing plants. Those operations freeze or can the corn for brands including Green Giant, Libby's and Birds Eye.

Economic advantages

Chris Dunton, manager of the Del Monte Foods processing plant in Sleepy Eye, said sweet corn gives farmers a nice option to build diversity and supplement their major crops. "The price is [also] set at beginning of the year before you ever plant it, so it gives a grower the opportunity to lock in that revenue stream," he said.

University of Minnesota Extension crops educator Dave Nicolai said the main reason Minnesota grows so much sweet corn is that it has just the right climate for it. Sweet corn grows best when daytime temperatures range from 75 to 86 degrees, he said, and in areas where rainfall is fairly consistent.

"We also have warmer days and cooler nights than other parts of the country, and that leads to better quality and sweetness," Nicolai said.

To assure freshness and minimize damage, Untiedt's crews pick the corn by hand early each morning. Each picker moves quickly between two rows with a burlap bag between his legs, using one hand and then the other to deftly snap off the ripe corn from the stalks on each side and chuck it into the bag.

Each bag is filled with four dozen ears, and when picking ends at midmorning, the bags are collected and hauled to a warehouse, layered in ice, and stacked on pallets. They stay cool until a truck driver makes a midnight delivery to the fairgrounds to transfer the corn into coolers, ready for Ribar to begin roasting when the fair opens.

Freshness is also paramount for processors. At the Del Monte plant in Sleepy Eye, trucks dump corn that's been harvested by machine onto an outdoor pad, and conveyor belts whisk it inside to a series of machines where the ears are husked, washed and sent through circular knives that follow the contour of the cob and cut the kernels off. The corn then moves through other washing and inspection stations.

"The process, start to finish, takes maybe 10 to 15 minutes, from an ear of corn with a husk on it to kernels in a vacuum-packed can that's packed in a case," said plant manager Dunton.

Del Monte contracts with about 300 growers, some of them third- and fourth-generation farmers, who grow sweet corn on about 12,000 acres near the plant, he said. Most of them mainly grow field corn and soybeans and add the sweet corn as a sideline on about 35 to 70 acres.

"We tell growers when to plant, and we have them plant several varieties with different maturity dates," he said. "So we schedule it all out so we can keep the plant supplied with nice fresh corn each day."

Seneca Foods Corp. is another large processor, with four plants in Minnesota that process sweet corn and other vegetables.

Noah Hultgren, president of the Minnesota Corn Growers Association who farms near Willmar in west-central Minnesota, grows about 350 acres of sweet corn on a couple of fields each year under contract with a Lakeside Foods plant in nearby Brooten.

Diversifying income

One advantage of a contract, said Hultgren, is that it provides a stable price per ton, in contrast to field corn where prices per bushel can fluctuate considerably. "It gives us another possibility for a crop to raise besides the standard [field] corn, soybeans and sugar beets," he said. "It's been steady over the years and has helped us with our income stream."

Hultgren said he also likes the fact that sweet corn is a short-season crop to take care of, and that Lakeside makes its own decisions about when the sweet corn is ripe, and uses its own equipment to harvest it.

For Untiedt, who grows most of his sweet corn for fresh markets, hand picking the old-fashioned way is manageable because the corn has been planted in staggered fashion over 60 days each spring, and harvested over 75 days in summer.

But he said things get especially busy during the 12-day State Fair.

"We all really enjoy doing it, and we've done it for quite a few years and we're proud that we do it, but it's an undertaking," he said. "By the end of the fair, we're pooped."

Tom Meersman • 612-673-7388