How Wheat Works


Without wheat, this man would have a hard time eating his lunch on the go. Without bread to make our sandwich technology possible, would human civilization have ever made it out of the Stone Age?
Adam Pretty/Taxi/­Getty Images

It's easy to take bread for granted. After all, what's a baguette but something to sop up the last of­ your soup with? When enjoying a sandwich or slice of pizza, many of us even throw the crust in the garbage, right next to the bread loaf heels. But bread and other wheat products -- like pasta and cookies, of course -- have become an important part of many human diets, especially as Earth's population continues to grow. How many times have you heard "bread and water" mentioned as the most basic meal imaginable?­

Humans have cultivated wheat for roughly 10,000 years, and archeologists have discovered evidence of milling operations in Asia that date back 75,000 years [source: Encyclopaedia Britannica]. But the origins of humanity's relationship with wheat go back even farther than that, all the way into the murky depths of prehistory. Long before the agricultural revolution, hunter-gatherers picked through the rich vegetation that surrounded them. Among the fruits and vegetables, they came across wheat stalks and quickly discovered the grains were edible.

­Today, humans devote more farmland to wh­eat than any other food crop. The plant dominates an estimated 500 million acres worldwide [source: Perdue University]. Combined, these fields yield a global harvest of approximately 661 million tons (600 million metric tons) each year [source: Encyclopædia Britannica]. Roughly 10 percent goes right back into the ground to ensure future harvests, but most of the rest goes on to feed humans and livestock around the world.

­In this arti­cle, we'll examine the wheat cereal grasses and look at just how we turn fields of grass into everything from the simplest porridge to the ritziest wedding cake.

Growing Wheat, the Organism

When wheat flowers fertilize, they produce grains, the edible portion of the plant. Here, we see the grains surrounded by bits of chaff in a person's palm.
When wheat flowers fertilize, they produce grains, the edible portion of the plant. Here, we see the grains surrounded by bits of chaff in a person's palm.
Riitta Supperi/Gorilla Creative Images/Getty Images

If you've ever flown on a commercial airliner and grabbed a window seat, there's a good chance you've witnessed the sheer magnitude of our dependence on wheat. Fields of the crop stretch for miles, dividing the landscape into a patchwork of green and gold farmland. It's easy to get lost in the big picture when gazing at such sights, but at the heart of it all, wheat is just a durable grass, and each plant produces a handful of nutritious grains.­

Wheat grows in a variety of climates and soils, but thrives best in temperate zones. It's an annual grass, which means it produces a harvest once a year. The tall plant typically boasts hollow stems, long leaves and heads of compacted flowers. Sometimes there are as few as 20 flowers, but some species sprout up to 100.

Believe it or not, the wheat plant's mission in life has nothing to do with Big Mac buns and Twinkies. The plant needs to grow to its full height and develop flowers, where reproduction will take place to ensure the plant's genetic future in the form of seeds. This yearlong lifecycle takes place in four stages. First, the plant goes through tillering, in which the subsurface crown produces leafs and lateral branches called tillers. Then, during the stem extension stage, the plant shoots up to its full height through a series of stem segments, joined to each other by nodes. Then, at the top, the stem terminates in a head or spike during the heading stage.

At this point, each head fertilizes its own flowers due to the movement of pollen from the male stamen to the female stigma. Once this happens, grain develops in the ripening stage, and the plant begins to wither and die. Each grain or kernel of wheat consists of a wheat plant embryo called a germ (as in germinate), protected by a thick outer coating called the bran and fueled by the protein-rich endosperm. These resources protect and nurture the wheat germ, allowing it to grow out of the soil into a new wheat plant.­

­The Earth is home to thousands of different wheat grasses, all categorized under genus Triticum in the Gramineae grass family. Given its importance as a global food crop, this kind of variety is really good news. Should a new plant disease wipe out one of these forms of wheat, there are still others that might be resistant. Scientists recognize the value of this biological diversity and have taken measures to store the world's wheat away in seed banks. Still, despite the threat organisms such as the black stem rust fungus pose, wheat growers concentrate most of their efforts on three key varieties of wheat.

  1. Triticum aestivum: Also known as "common wheat," we use this variety for flour and bread making. Experts suspect this particular grass originated in the Middle East's Fertile Crescent. Today, farmers cultivate nearly 100 of the 200 known varieties of common wheat.
  1. T. durum: Durum wheat primarily winds up as semolina, the grains used to make macaroni, spaghetti and other noodles. There are eight known varieties.
  1. T. compactum: A subspecies of T. aestivum, club wheat produces a softer flour and is mostly used in cakes, cookies and crackers.

But how do we harvest the wheat grains and turn them into delicious foods? Skip to the next page to find out.

Processing and Eating Wheat

While only the heads of wheat plants contain enriching human foods, farmers usually harvest the dried stems and leaves for use as hay, which provides livestock with food and a comfortable place to sleep.
While only the heads of wheat plants contain enriching human foods, farmers usually harvest the dried stems and leaves for use as hay, which provides livestock with food and a comfortable place to sleep.
Imagemore/­Getty Images

­Farmers grow wheat as either a winter or spring crop, depending on how severe winters are in the region. In milder climates, planting takes place in the fall with harvest following between June and August, depending on the duration of winter. Where winters are a little more intense, farmers plant as soon as the soil has thawed and harvest in early fall.

Modern farmers typically use a combine harvester to collect their wheat, but the scythe, sickle and flail still see significant use in developing countries. The first task is pretty simple: cut the heads from the top of the wheat plants and then thresh them to remove the grains from the rest of the head, called chaff. The grains are divided from additional plant fragments, cleaned and taken to a mill, where any separation of bran, endosperm and germ takes place.

To separate the three elements, farmers either crush the wheat with grinding stones or pass them through automated steel cylinders. Mill operators usually add a small amount of water to the grains, as this toughens the outer bran and softens the inner endosperm, making it easier to split the two. Rollers typically flatten the wheat germ, allowing it to be sifted out from the rest of the flour. In modern mills, the type of flour produced depends on what stage operators remove it from the milling cycle.

Wheat grain contains several key nutrients. The outer bran covering contains three major B vitamins, trace minerals and dietary fiber. The endosperm, however, takes up most of the room and contains protein, carbohydrates, iron, riboflavin and thiamine. Not to be outdone, the germ (or wheat plant embryo) contains a small portion of B vitamins and trace minerals as well.

­While early humans consumed these grains raw, they eventually began using tools to pound the grain and then adding water to the crushed kernels to form a wholesome gruel. The uses and properties of wheat foods vary depending on what combination of bran, endosperm and germ harvesters use. Take white bread and bleached white flour, for instance. In these products, both the bran and the endosperm have been removed to ensure smoother texture and longevity. The germ contains fat, which can turn rancid in flour if not properly stored. But wheat germ still contains a number of key nutrients, including protein, and is used separately in many products.

Whole wheat products contain all three parts of the wheat grain, offering the largest array of nutrients. When separated from the rest of the grain, bran also goes it alone for use in animal feed and foods such as bran muffins and breakfast cereals.

­Before you grab a bowl of cereal or a bottle of wheat beer, explore the links on the next page to learn even more about agriculture.

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More Great Links

Sou­rces

  • "Cereal." Britannica Online Encyclopædia. 2008. (Sept. 25, 2008) http://www.britannica.com/EBchecked/topic/103301/cereal
  • "Cereal farming." Britannica Online Encyclopædia. 2008. (Sept. 19, 2008)http://www.britannica.com/EBchecked/topic/1343927/cereal-farming
  • "Cereal processing." Britannica Online Encyclopædia. 2008. (Sept. 19, 2008)http://www.britannica.com/EBchecked/topic/103350/cereal-processing
  • Gage, Fran. "Wheat into Flour." Gastronomica. 2006. (Sept. 19, 2008)http://www.gastronomica.org/issues0601.html
  • "A Kernel of Wheat." Wheat Foods Council. (Sept. 23, 2008)http://www.mainebread.com/images/wheat_diagram_big.jpg
  • Kirby, E.J.M. "Botany of the wheat plant." Bread Wheat. 2002. (Sept. 23, 2008)http://www.fao.org/DOCREP/006/Y4011E/y4011e05.htm
  • Posner, Elieser S. and Li, Yuzhou. "Method of separating wheat germ from whole wheat." Free Patents Online. Jan. 22, 1991. (Sept. 23, 2008)http://www.freepatentsonline.com/4986997.html
  • Stalcup, Larry. "Wheat Hay Cattle Love It." Beef Magazine. July 1, 2004. (Sept. 23, 2008)http://beefmagazine.com/mag/beef_wheat_hay_cattle/
  • "Wheat." Britannica Online Encyclopædia. 2008. (Sept. 19, 2008)http://www.britannica.com/EBchecked/topic/641558/wheat
  • "Wheat." New Zealand Baking Industry Research Trust. 2004. (Sept. 23, 2008)http://www.bakeinfo.co.nz/school/school_info/wheat.php
  • "Wheat." Purdue University Center for New Crops & Plants Products. Sept. 29, 1997. (Sept. 22, 2008)http://www.hort.purdue.edu/newcrop/Crops/Wheat.html
  • "Whole Wheat." The World's Healthiest Foods. 2008. (Sept. 19, 2008)http://www.whfoods.com/genpage.php?tname=foodspice&dbid=66

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