Advanced BioFuels USA

by Susanne Retka Schill (Ethanol Producer Magazine)  Ethanol producers have sustained adequate production yields in 2020, despite low-quality corn from last year’s harvest. While experts aren’t sure why problems haven’t arisen, improved enzymes and yeasts have probably helped plants stay ‘dialed in.’

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The 2019 growing season presented a wide array of weather-related setbacks for the corn crop from planting to harvest—with some growers harvesting the corn rows they could reach in spite of snow and mud in winter and spring. For ethanol producers, the low test weights, high moisture and high damage counts raised concerns that ethanol yields would take a hit.

“Quality was lower,” says Randy Doyal, CEO of Al-Corn Clean Fuel, in Claremont, Minnesota. “The biggest problem we have seen is with the weakness of the kernel. Damaged, broken corn produces higher fines, resulting in problems with flowability in corn bins and plugging of feed hoppers. [Ethanol] yield is down a touch, probably about par with the amount of material removed during multiple bin cleanings.”

Further west, Ryan Carter, general manager of Tharaldson Ethanol in Casselton, North Dakota, is seeing a wide range of corn quality coming into the plant. “It did not affect the yield like you would have thought. …”

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“The microbes aren’t necessarily going to survive into the fermentation process,” Gleason (Stephanie Gleason, senior manager of technical service at Phibro Ethanol Performance Group) says. “But the byproducts made by the molds can influence fermentation negatively. With bacterial contamination, organic acids are typically the problem.”

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Chris Ashworth, technical services manager at Lallemand Biofuels & Distilled Spirits, attributes the better-than-expected ethanol yields from questionable corn quality to plants getting better at their processes. “They’ve got their front ends dialed in,” he says. “Plus, the enzymes on the market now, and the yeast offerings that we and our competitors have out there, are better in yield than they used to be. All of that has translated into not losing as much yield as we thought we would.”

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Cyclical Quality
Plants also see yield losses every year when they switch to new crop corn, Ashworth says. “Corn coming straight out of the field doesn’t produce as well as corn that has been stored a month or two. This fall was very similar. Then the yields came back as they normally would.”

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The Case for a Starch Standard

The standard grade used by the U.S. ethanol industry—U.S. No. 2 yellow dent corn—bears little resemblance to what ethanol producers actually need, says Robert Piggot, global technical manager, Lallemand Biofuels & Distilled Spirits.

The standard for No. 2 sets a minimum test weight of 54 pounds per bushel, a maximum of 5 percent total damaged kernels, and a maximum of 3 percent broken corn and foreign material (BCFM).

Moisture isn’t even a part of the official specification, Piggot points out, and differences of 1 to 2 percent moisture make a big difference. “Increased moisture takes more mill amps to grind it, you can’t store it as long, and you get less starch,” he says. “If you’ve got 1 percent more by weight of water, that is roughly 0.68 percent starch you don’t have.”

Test weight and BCFM aren’t as important to an ethanol plant as starch, he says. “What we should be specifying in our purchasing is starch content.” The test isn’t difficult, he says. NIR (near infrared) testing equipment can give moisture, protein and starch levels in one analysis in less than a minute.

Piggot knows of two seed companies that have developed high-starch corn varieties. “There are hybrids with 3 percent more starch,” Piggot adds, “but they cost a bit more so farmers aren’t going to grow them unless they get paid more.” 

The plant would gain enough benefit to share with the farmer, Piggot says.  READ MORE