That humble loaf of bread sitting in your kitchen is a marvel.
No one knows it better than Brad Seabourn, who directs a team of scientists at the USDA's Hard Winter Wheat Quality Laboratory, in Manhattan, Kansas.
"There's a tremendous amount of science involved in what we take for granted in a simple loaf of bread," he says. "The industry is working with a biological material -- wheat -- that varies tremendously every single year across every growing season, and they're trying to make this same product fit into this same bag with the same dimensions every single time."
At the front end of the industry are breeders, from seed companies or academia, creating new wheat varieties. At the other end are farmers, striving to grow the high-yielding, high-quality wheat showcased by the National Wheat Yield Contest.
In between them are Seabourn and his team of scientists. More than 95% of all hard winter wheat varieties grown in the country pass through their doors. They put those kernels through their paces -- crushing them, mixing them with water and then stretching, pulling, squishing and baking their dough -- to see if they are fit for the grocery stores and kitchen pantries of America.
Only 1 to 2% of the varieties the lab tests will ever make it to commercialization. "We help wheat breeders pick the winners and the losers, and make sure only the winners go through," Seabourn explains.
The lab is one of four run by USDA. The other labs test soft winter wheat, hard red spring and durum wheat. The Manhattan lab specializes in hard winter wheat grown primarily in the Great Plains and destined for the multipurpose flour that makes the nation's breads and rolls.
Both public and private breeders send their winter wheat lines to the Manhattan laboratory, which also analyzes a continuous stream of samples arriving from the winter wheat harvest starting in Texas in June and rolling through October in Montana and the Dakotas.
FROM KERNEL TO FLOUR
A wheat kernel's first experience in Manhattan is a rough and tumble journey through the mill.
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There, scientists clean each sample and run part of it through a series of small machines, each looking a bit like a large printer. One measures their size. Another crushes a sample of kernels and tests their hardness and moisture.
Eventually, miller Jeff Gwirtz sends them through the hard, crushing corrugated rolls of the Tandem Bühler mill, which sloughs off their outer hulls. A second, smoother pair of rollers grinds and squeezes them into the fine flour most Americans would recognize.
By the time the wheat samples leave the mill as flour, the laboratory's scientists have a valuable trove of data. They know the kernel hardness -- how much force it takes to crush that kernel. Too hard and the mills will spend precious energy milling their wheat. Too soft and the flour will be clumpy and clingy and require extra sifting.
They know the protein content -- how much of the all-important gluten molecule inhabits each kernel. Ideally, all-purpose flour will have a protein content of around 11%, just the right amount of strength and stretchiness. Realistically, millers and bakers must sort, blend and plan to accommodate the range of winter wheat protein contents they receive, from as low as 8% to as high as 14%.
THE DOUGH CRITICS
Transformed into bags of silky white flour, the winter wheat varieties return to the laboratory, ready for a series of punishing tests.
As a machine called the mixograph tests the dough, its needle scratches out a long series of spikes on a rolling sheath of paper. Like an EKG (electrocardiogram), this signature is truly the heartbeat of the dough. It tells the lab just how strong and stretchy the dough is, how long it takes to mix and how long past that optimum time it can handle additional mixing before collapsing.
This is everything to a baker, Seabourn explains. "Bakers can be working with 1,000 to 2,000 pounds of dough in a giant vat, so it's really important for them to know how long it will take to mix that vat and -- if they go seconds or minutes beyond that optimum time -- when will that dough start to break down?"
In one room, lab technician Kevin Fay is literally spending his day blowing bubbles. He operates the alveograph -- a toasterlike machine that pipes warm air through a patty of dough, causing it to swell into a large bubble that eventually pops and collapses on itself.
The bubble test reveals the stretchiness ("extensibility") and strength ("resistance to extension") of each dough sample. Too stretchy and weak, and the dough will not hold up well enough to form a loaf of bread. Too strong and resistant, and the dough will be unworkable.
These extremes are not always a lost cause, Seabourn is quick to point out. Stretchy, floppy doughs that make lousy bread also happen to make excellent tortillas and pretty good Asian noodles. He quotes a previous director of the lab, Karl Finney: "There is no such thing as poor-quality wheat; there's just wheat we have yet to find a use for."
THE BAKER'S FINAL VERDICT
In the baking lab, supervisor Margo Caley runs the show. Like any baker, she deftly kneads, folds, stretches and pats dough samples all day long. But, she is also collecting an array of data points along the way -- how the dough responds to kneading, how quickly or slowly it rises, or whether it stretches or tears easily.
As it leaves Caley's hands, each wheat sample faces its final crucible: a trip through the industrial-sized oven. As the smell of baking bread spreads rapidly throughout the entire laboratory, she removes each tiny, 100-gram test loaf, slices and scrutinizes it for the ultimate verdict on a burgeoning winter wheat variety.
Is it light and fluffy? Dense and uneven? Crumbly or moist? Will a knife bearing a lunchtime load of peanut butter or jelly slide across it easily, smoothly? Or was the dough too weak to contain the gases that built up during baking, producing gaping holes in the grain that cause jelly drips and sticky fingers?
READING THE WHEAT
Like crumbs of bread, the lab's wheat data leaves a trail around the world. Information on the quality of the year's wheat harvest is sent to industry trade groups, which use it to promote American wheat in export markets abroad.
Data on experimental wheat lines are returned to the breeders, who decide if and how to move forward with that variety. It takes 10 to 12 years to produce a single variety of wheat for commercialization to the tune of $1 to $2 million. In addition to these quality tests, a wheat variety must pass other agronomic goals, as well, such as disease or insect resistance, heat and drought tolerance, or standability.
"Farmers are operating in a constantly changing landscape, so the breeder is always trying to predict what they will need 10 years from now, so they have just the right variety to meet farmers' needs then," Seabourn says.
"I'm always just in awe of what breeders do," he adds. "They're out there working silently for the American consumer, getting very little credit and yet regularly producing a fully safe, nutritional, uniform and bountiful product all the time. We owe them a lot."
And, they in turn owe the wheat quality labs of America -- the "firewall for wheat quality," as Seabourn calls it.
"If a wheat variety isn't functional, if you can't make a loaf of bread with it, then we don't want it out there," he says.
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