Extending corn supply with wheat not so easy

Wheat isn’t going to be an easy substitution like grain sorghum. While it is, indeed, the dominant feedstock in several regions such as western Canada and the UK, those plants are designed to handle wheat.
By Susanne Retka Schill | March 11, 2013

Reports this past week suggest tight corn supplies has one ethanol producer looking for another well-known feedstock to stretch corn supplies – wheat. 

DuPont’s Edgar Seward, director of North American sales, biorefineries, actually predicted this would be the case when speaking at the ACE conference last August. “For a lot of folks, this is going to be a very different crop,” he said. “You’re going to see people do things this year that normally they wouldn’t consider,” he said. DuPont is hearing from ethanol producers on the hunt for the cheapest starch available. That’s prompting questions about grinding 30 percent wheat or adding sorghum to the mix at plants that were previously relying completely on corn.

In my April feature article that’s just gone to press, I learned that sorghum can be substituted for corn pretty easily. At least one Kansas producer says they can see no difference in ethanol yield when using corn or sorghum, and in fact, dump the two grains in the same bin. The only difference is that grain sorghum needs a small amount of enzymes added to deal with the tannins. Grain sorghum production, though, is pretty much limited to the High Plains states where most of the ethanol producers already freely mix the two feedstocks as needed.

Wheat is another matter. Reuters reported last week that Poet Biorefining-Portland (Ind.) was bidding on soft red winter wheat. They quoted Chris Manns, president of Traders Group Inc. as saying, "They can do up to 20 percent with wheat before having to completely shift their plant over. I have heard it is being done in some areas depending on price and availability."

Checking out the plant’s web page, sure enough, on Monday it showed cash wheat bids at $7.11, reporting the April futures at $7 and a basis of 11 cents. That compares with their bid on April corn at a cash price of $7.63, reporting a 54 cent basis on the April futures contract of $7.08.

Wheat isn’t going to be an easy substitution like grain sorghum, though. While it is, indeed, the dominant feedstock in several regions such as western Canada and the UK, those plants are designed to handle wheat.

A few years back I wrote about Canadian ethanol producers’ use of wheat. The prairie provinces are well-known for the production of hard red spring wheat – the high protein, strong gluten wheat used for bread flour. Farmers were hoping for a new market for their weather-damaged HRS wheat. Ethanol producers, though, were trying to convince farmers to raise lower-protein soft white winter wheats. If you’re a baker, you’ll know why.

The high protein and strong glutens are what makes bread dough elastic, helping the sponge raise nicely as the yeast do their work and release CO2.  Soft wheats are used for cakes and crackers where you want a different texture. Hard wheats have protein levels of 12 to 15 percent while soft wheats tend to be 8 to 10 percent protein. While corn has protein, it doesn’t have gluten. (A website on celiac disease points out that what the corn industry calls corn gluten is a misnomer, it isn’t the same as wheat gluten.)  

The protein and gluten in wheat increases the viscosity of the mash in the ethanol process which is dealt with through the addition of the right enzymes. The higher protein and lower starch levels also increase the nonfermentable solids. That, in turn, affects the back end of the process because the greater amount of wet cake increases the load on the centrifuges and driers. One positive side to mixing corn and wheat is that the corn oil helps with wheat’s tendency to foam. In fact, many Canadian producers use a small amount of corn to deal with the foaming issue.

Thus, introducing wheat into a corn ethanol plant is serious business. I can just imagine the work that Poet’s process and research folks have done to make sure they have considered all the things that will be impacted and make the proper adjustments. With margins as tight as they are, and wheat not a slam-dunk cheap feedstock, it’s important they get it right. My guess is that if the Portland plant successfully uses wheat, we may see more Poet plants in areas with soft wheat surpluses look to extend their corn supply. I would also guess that given the fact that many ethanol producers are independents without the sort of backup that Poet has through its R&D and process design groups, we aren’t going to see a lot of wheat going through corn ethanol plants.