Seeking Sound Corn: Quality Matters

Do ethanol plants need to improve their grading practices?
By Holly Jessen | September 12, 2011

Inbound corn quality matters. That’s the message Charles Hurburgh Jr. wants to send ethanol plants.

Most ethanol plants purchase No. 2 corn, which allows for 5 percent damage. But Hurburgh, professor in charge of the Iowa Grain Quality Initiative at Iowa State University, suspects more damaged corn is sneaking in than is realized. “My observation has been that there’s an awful lot of hand waving that goes along with grading and [grading] is basically not done in an exhaustive way,” he tells EPM.

It’s well known that vomitoxin, a type of mycotoxin that was a big problem in 2009, is concentrated in the distillers grains and can cause problems if fed to livestock. Damaged corn can also impact the fermentation process, requiring additional rescue antibiotics or sulfuric acid between batches. While those problems can be righted, it’s a cost and a hassle best avoided, Hurburgh says. “Professionalism on input quality will pay rewards, no matter what,” he says.

The quality of the corn entering an ethanol plant is only as good as the grading program and the vigilance and training of the graders. Plants that don’t make this a priority will receive damaged corn. “I don’t think I am telling any secrets out of school—if grading is not monitoring quality, you’re going to get whatever you’re calling No. 2 corn,” he says. “And if you accepted it, you are calling it No. 2 corn whether it is or it isn’t. That 5 percent will go to 10 in a heartbeat, because the person shipping knows you are not checking.”

It isn’t known yet whether the 2011 corn crop will suffer damage, and the 2010 crop looked great. So, why worry about corn damage? It’s the wet and highly damaged supplies from 2009 that are the potential problem. “We still have a lot of 2009 corn put away in storage and actually being blended out,” he says. “I would guess that we have another year or so for the potential for high-damage corn.” Even in years with no damaged corn in the system, Hurburgh advocates vigilance. Those are the times that foster the hand-waving mentality for grain grading. “It lulls you to sleep,” he says, adding that plants need to be prepared to react quickly to changes in corn quality. In addition, with corn yield growing yearly, grain grading will become even more important. “The more grain we handle, the more there will need to be discipline in the system,” he says. “That’s what grain inspection does.”

Professionals in Place

No two ways about it—ethanol plants need professional grain inspection at grain receiving, Hurburgh says. That could mean hiring a third party grain inspection firm, which is the practice of many large ethanol processors such as Archer Daniels Midland Co. and Cargill Inc. “You won’t find them using house grades,” he says, adding that soybean processors also use third-party services for grain grading.

There’s resistance to the idea within the ethanol industry, however. Although he’s talked to many plant managers who say it would be far too expensive, Hurburgh isn’t sure that’s true. “I’ll stick my neck out,” he tells EPM. “I believe that a plan could be worked that would allow the use of third-party inspection—certainly in a 100 MMgy plant. I don’t know about a 50 MMgy plant, obviously there is an economy of scale.”

Even if an ethanol plant didn’t work with a company that had an on-site grain inspection laboratory—such as is the case at the 35 MMgy Cargill ethanol plant in Eddyville, Iowa— there are ways to incorporate third-party testing. An ethanol plant could contract with a third party to do blind checks, meaning the in-house grader is periodically checked at random against an official grader. “The validation makes sure that they are not getting biased one way or another with respect to the official system,” he says. Hurburgh also recommends in-house graders receive professional training. This is a step that won’t cost much but will pay off big. “House graders can be just as good with the right training and validation,” he says.

There are many avenues for grain grading training. For example, the USDA’s Grain Inspection, Packers & Stockyards Administration offers eLearning opportunities on its website. And, although it varies from state to state, courses or workshops are often offered through extension services. In Texas, grain-grading workshops were offered in May—something the Texas AgriLife Extension Service has been doing for the past 21 years, says Steve Amosson, professor and economist. Staff from Hereford Renewable Energy, a 105 MMgy ethanol plant in Hereford, Texas, have been among the training’s attendees. “At these grain prices, you cannot afford a mistake,” Amosson tells EPM.

Hurburgh also understands that with plants unloading a truck every couple minutes at times, it’s not feasible to do exhaustive grading for every load. He recommends taking composite samples from each seller, for later grading. The trade-off for speed is that not every bad load of corn will be identified up front. In the long run, however, the plant will be able to increase its average corn quality using this strategy. “If someone is taking liberties with you, there are market ways to discipline that,” he explains, adding that it’s typically price.

Finally, he recommends plants test protein periodically. Protein levels are the single biggest factor that determines ethanol yield, as protein and fermentable starch are inversely related, meaning if protein levels are high, starch levels will be low. A 1 percent downward shift in protein, from 8 to 7 percent, also will mean the protein content in distillers grains will likely go down about 3 percentage points, from about 26 to 23 percent protein. “They should know, on an average basis, what the protein trends are,” he says, “because that’s going to affect what their guarantee can be on the distillers grains.”

Other factors, such as test weight, moisture, broken corn or foreign material don’t affect yield as much. In 2009, damaged corn with low test weight didn’t have a significant impact on yield but did mean more spoilage in storage, he says. In fact, low test weight corn can be lower in protein, translating into higher yields.

Producers Chime In

What are ethanol producer’s thoughts on corn grading? Steve Roe, general manager of Little Sioux Corn Processors LP, agrees that corn grading is very important business at an ethanol plant. The 92 MMgy ethanol plant in Marcus, Iowa, does not use a third-party grading company because it’s simply too expensive, he says.

To avoid accepting off-grade corn, the plant has three to four employees working to weigh trucks and grade corn. Still, he acknowledges that bad corn can sometimes slip by. “We probe trucks twice to determine corn grades,” he says. “The biggest issue for us is trucks that are layered and attempt to hide off grade. This is not an isolated issue.” That practice also occurs within industries other than ethanol, he adds. “If we catch firms sending layered corn, they are discounted very heavily or the load is rejected.”

GreenField Ethanol, which operates four ethanol plants in Canada, has a comprehensive corn quality assurance program, says Ken Robertshaw, the company’s director of corn procurement. At the 60 MMgy Johnstown, Ontario, ethanol plant—the largest of GreenField’s plants with a combined capacity of more than 160 MMgy—three full-time corn analysts work to process 70 loads of corn daily, five days a week and 13 hours a day. These employees process all corn and distillers grains at the plant, including the required shipping documentation.

Like Roe, Robertshaw says that good quality assurance programs are important in any industry, including the ethanol industry. “Having solid data from the front gate, from the process, and through to the final products gives the plant the understanding it needs to operate at its peak efficiency,” he says. “This knowledge allows us to work with the supplier to set incoming corn specifications that will yield the best results for both parties.”

In any crop year, GreenField screens incoming corn for mycotoxins. When the vomitoxin problem was at its peak, the company provided suppliers with load-specific vomitoxin data so they could manage their inventories. The company has observed a significant drop in vomitoxin levels from the bad 2009 crop year, he adds.

All GreenField corn analysts are trained to grade in accordance with Canadian Grain Commission guidelines and all loads of corn are sampled and tested using CGC methods. While the company does use in-house staff for corn grading, it also uses third-party validation, including sending a weekly random sample to the CGC and using that data internally to cross-check the accuracy of company grading. Once a year, the plant’s corn grading facilities and procedures are audited by a third party to confirm the plant is complying with CGC regulations. Finally, the truck scale is calibrated quarterly to Canadian weights and measures standards by a third-party vendor. These and other measures help assure the plant’s supplier that its grading practices are consistent and fair, Robertshaw tells EPM. “[It] also allows us to accurately track incoming corn quality and make proactive process adjustments when required.”

Author: Holly Jessen
Associate Editor, Ethanol Producer Magazine
(701) 738-4946


ON THE WEB: Examples of damaged and sound corn kernels can be found on the USDA Grain Inspection, Packers & Stockyards Administration website. Go to education & outreach, eLearning and view visual reference images. Visit: