Ready-to-eat cereals are served in nine out of ten American households.
Cereal is a grain food eaten as a main course for breakfast and is typically served with milk or cream. Some cereals, such as oatmeal, require a few minutes of cooking. Other hot cereals, called "instant," can be prepared in less time. Cold, ready-to-eat cereal, on the other hand, can be eaten right out of the package.
A healthy start
Cold, ready-to-eat breakfast cereals developed because of religious beliefs. In 1829, American clergyman and vegetarian Sylvester Graham (1794–1851) invented the graham cracker. Made from coarsely ground whole wheat flour, the graham cracker was part of a vegetarian diet he developed to cure intemperance (excessive intake of alcoholic drinks).
In the 1860s, influenced by Graham, Seventh-Day Adventists, who believed that healthy living included eating the right kinds of food, established the Western Health Reform Institute in Battle Creek, Michigan, later renamed the Battle Creek Sanitarium. John Harvey Kellogg (1852–1943), the head physician at the institute, invented a product called Granola, made from wheat, oats, and corn that had been mixed, baked, and coarsely ground. In 1894, Kellogg and his brother Will Keith (better known as W.K., 1860–1951) produced the first precooked flaked cereal made of wheat. They called the cereal Granose. This product was the predecessor of Kellogg's Corn Flakes®.
In 1895, C.W. (Charles William) Post (1854–1914), John Kellogg's patient, started his own cereal business with the introduction of Postum® cereal coffee, an "un-caffeinated" beverage advertised as a health food. Two years later, he produced a ready-to-eat cold cereal called Grape-Nuts®, named after the ingredient grape sugar and the cereal's nutty flavor. This was soon followed by a corn flake cereal called Post Toasties®.
Kellogg's and Post's success led many others to open cereal factories, but those businesses quickly failed. The success of the two cereal pioneers was partly the result of clever advertisements that presented their healthful cereals as quick, convenient, and tasty breakfast foods. To this day, Kellogg and Post cereals continue to be consumed by the American public. Ready-to-eat cereals are served in nine out of ten American households. Flaked cereals make up about one-third of ready-to-eat cereal sales.
Grain is the most important raw material in any breakfast cereal. The grains most commonly used are corn, wheat, oats, rice, and barley. Most cereals contain other ingredients, including salt, yeast, sweeteners, flavoring agents, coloring agents, vitamins, minerals, and preservatives. Some cereals, such as oatmeal (usually served hot) and shredded wheat, contain no additional ingredients.
The sweeteners used in cereals include malt extract (a sweet substance made from barley), white sugar, brown sugar, corn syrup, honey, and molasses. Some natural cereals are sweetened with concentrated fruit juice. Flavors, such as chocolate, cinnamon, and fruit may be added. Nuts, dried fruit, and marshmallows may also be added.
Vitamins and minerals that are lost during cooking are added. The most important is Vitamin B1, most of which is destroyed by heat. To prevent cereals from discoloring and becoming stale and rancid, the antioxidants BHA and BHT are added as preservatives.
The Manufacturing Process
Ready-to-eat breakfast cereals may come in the form of flaked, puffed, and shredded cereals. Some have been formed into particular shapes, such as circles or letters. Others come mixed with other ingredients, including nuts, dried fruits, and flavors.
Preparing the grain
1 Whole grains are received at the cereal factory, inspected, and cleaned. The grains may be used as such or undergo some processing. Often, whole grains are crushed between large metal rollers to remove the outer layer of bran. Then, they are ground more finely into flour.
While employed at the Battle Creek Sanitarium, W. K. Kellogg and his brother, John Harvey, accidentally invented flake cereals. One day, they made some wheat porridge that they planned to put through large rollers for bread-making. The brothers got called away and left the mixture standing. By the second day, the mixture had dried out. When they passed the mixture through the rollers, large, thin flakes came out. They then baked the flakes, which turned crispy. The wheat flakes, which they called Granose, soon became popular among the patients. Later on, W.K. found that corn made better-tasting flakes. In 1906, he established the Battle Creek Toasted Corn Flake Company, which later became known as the W. K. Kellogg Company.
2 Whole grains or partial grains, such as corn grits, are mixed with water, sweeteners, salt, flavoring agents, vitamins, and minerals in a large pressure cooker. The time, temperature, and speed of rotation vary with the type of grain being cooked.
3 The cooked grains are moved to a conveyor belt, which goes through a drying oven. The cooked grains retain enough water to form a soft, solid mass that can be shaped as needed.
4 If flour is used instead of whole or partial grains, it is cooked in a cooking extruder. This device consists of a long screw inside a heated housing. The movement of the screw mixes the flour with water, flavorings, salt, sweeteners, vitamins, minerals, and sometimes food coloring. The screw moves the flour mixture through the extruder, cooking it in the process. The flour comes out of the extruder as a ribbon-like dough. A rotating knife cuts the dough into pellets (small masses), which are then processed the same way as cooked whole or partial grains.
Making flaked cereal
5 The cooked grains are allowed to cool for several hours in order to become tempered, or to allow the moisture content of each grain to get evenly distributed. The tempered grains are then flattened between large metal rollers under tons of pressure, emerging as flakes.
6 The flakes are moved by conveyor belt to ovens in which they are tumbled in a blast of very hot air to remove the remaining moisture. During this process, the flakes are toasted to the desired color and flavor. The dough pellets made from flour (see above) can be made into flakes the same way.
Making puffed cereals
7 Rice grains are usually used to make puffed cereals. The rice grains are cooked, cooled, and dried. As with flaked cereals, the rice grains are passed between metal rollers but are only partially flattened. This process is called bumping.
8 The bumped rice grains are dried again and put into a puffing gun, an oven that holds very hot steam and very high pressure. The oven is quickly opened, reducing the pressure and causing the rice to inflate. The dough pellets from flour can be puffed the same way.
Wheat grains can also be used to make puffed cereals. While the rice grains require no pretreatment, the wheat grains have to have the bran, or outer coat, removed. This may be done in one of two ways. In a process called pearling, the bran is worn off by putting the wheat grain between grindstones. The bran may also be removed by soaking the wheat grains in salt water, which hardens the bran, causing it to break off the grain during puffing.
Making shredded cereals
9 Whole wheat grains are used to make shredded cereals. The wheat grains are boiled in water to let them acquire moisture. The cooked grains are cooled and allowed to temper. Two metal rollers are used for shredding. One roller is smooth, while the other is grooved and has a metal comb. The softened wheat is pushed through the rollers under pressure and shredded in a continuous ribbon by the teeth of the comb. A conveyor belt catches the ribbons, stacking them into layers. The layers are cut into tablets and baked in a very hot oven until the outside is dry and toasted to the desired color. The shredded cereals are put into another oven set at a lower temperature to dry the inside of the cereals. Shredded cereals may also be produced from the dough pellets made of flour.
Making other cereals
10 Cereals can be made from cooked dough into different shapes, such as circles and letters of the alphabet, using a cooking extruder. A mold of the desired shape is attached to the end of the extruder. The ribbon of cooked dough that comes out of the extruder is then cut into smaller pieces by a rotating knife. The shaped pieces are then partially puffed.
11 Granolas are made by mixing rolled oats and other ingredients, such as brown sugar, nuts, dried fruits, and flavoring agents, and cooking them on a conveyor belt moving through an oven. The cooked mixture is then crumbled to the desired size.
Hot cereals are made by first processing the specific grains—rolling or cutting oats, cracking wheat, or coarsely grinding corn into grits. The grains are partly cooked so that consumers can cook them quickly in hot water. Salt, sweeteners, flavoring agents, and other ingredients may be added to the partly cooked mixture.
12 After shaping, the cereals may be coated with vitamins, minerals, sweeteners, preservatives, food colors, and flavors, such as fruit juices. A thick, hot syrup may be sprayed on the cereal in a rotating drum. When dry, the syrup forms a white frosting.
13 Most cereals are packed in airtight, waterproof plastic bags within cardboard boxes to protect them from spoilage due to moisture. Some cereals, such as shredded wheat, that are not damaged by moisture are placed directly into cardboard boxes or in cardboard boxes lined with plastic. The box tops are sealed with a weak glue to allow for easy opening.
14 The cereals are packaged by an automated machine at a rate of 40 boxes per minute. The completed boxes are packed into cartons that may each hold 12, 24, or 36 boxes. The sealed cartons are then shipped to retailers.
Cleanliness is very important in cereal manufacture. The cereal grains are inspected for any foreign matter when they arrive at the factory and during cooking and shaping. The machines are made of stainless steel, allowing for thorough cleaning and sterilizing with hot steam.
To ensure proper cooking and shaping, workers constantly check the temperature and moisture content of the cereal. Vitamin and mineral contents are measured so that they can be accurately listed in the nutrition information on the packaging. Filled packages are checked for uniform weights.
"ENRICHING" AND "FORTIFYING"
Some cereals may lose significant nutrients (vitamins and minerals) during the manufacturing process. For example, the B vitamins are especially likely to be destroyed by heat. After the cooking processes and other heat treatments, the cereals are "enriched" with the nutrients that have been lost. Some cereals may be "fortified," or treated with additional nutrients. Heat-resistant nutrients, such as vitamins A and E, may be cooked into the cereal.
Stored cereal is tested to determine its shelf life, which is then indicated on the box labels. Testers monitor the freshness of cereal over a certain period of time by subjecting it to temperatures and humidity levels that are higher than normal to speed up spoilage.
A new development in cereal technology is the twin-screw cooking extruder, in which two screws scrape each other clean as they rotate. This action moves the dough more smoothly through the extruder. Using this extruder along with computers that accurately control temperature and pressure cuts the manufacturing process from 24 hours to less than half an hour.
The cereal industry has responded to the consumers' demand for foods that are more healthful. New cereals in the market include those with added calcium. In the late 1990s, the U.S. Food and Drug Administration (FDA) allowed food manufacturers to put health claims on their product labels, including the benefits of fiber-containing grains and soy protein in lowering the risks of heart disease. Since then, cereals rich in fiber and soy protein have continued to be developed. "Organic" cereals, or cereals made from grains grown without the use of pesticides and/or fertilizers, have also been introduced.
- A substance that prevents food from discoloring or going stale.
- The outer coat of a cereal grain.
- conveyor belt:
- A continuous moving belt that transports objects from one place to another.
- corn grits:
- Coarsely ground corn.
- A soft mixture of flour, water, and other ingredients, such as salt and sweeteners.
- Also called bulk or roughage, it refers to the indigestible part of plant foods.
- Finely ground grains.
- The seed or fruit of a cereal grass.
- An ingredient that prevents a food from spoiling.
- Odor or taste of decomposed fats or oils; spoiled.
- rolled oats:
- Oat grains that have had their outer coverings removed, then flattened into flakes with rollers.
- shelf life:
- The length of time a cereal may be stored before it starts losing its freshness.
- The process of allowing cooked grains to sit for several hours in order to even the distribution of moisture.
- whole grain/whole wheat grain:
- A cereal grain with the germ (embryo) and bran (edible seed coat) intact.
- A substance used to help dough rise.
For More Information
Epstein, Rachel. W.K. Kellogg: Generous Genius. New York, NY: Grolier Publishing Company, Inc., 2000.
Fast, Robert B., and Elwood F. Caldwell, eds. Breakfast Cereals and How They Are Made. 2nd ed. St. Paul, MN: American Association of Cereal Chemists, 2000.
"How Did They Do That?" Food Insight (January/February 2001): pp. 2–3.
Adriano, Jackie, and Tamar Genger. "Not Your Mother's Cream of Wheat." Nutrition Action Health Letter.http://www.cspinet.org/nah/01_02/index.html (accessed on July 22, 2002).
"Post Heritage." Kraft Foods.http://kraftfoods.com/postcereals/heritage_1.html (accessed on July 22, 2002).
"Quaker History." Quaker Oatmeal.http://www.quakeroatmeal.com/Archives/History/Indexoat.cfm (accessed on July 22, 2002).
Breakfast cereal is a processed food manufactured from grain and intended to be eaten as a main course served with milk during the morning meal. Some breakfast cereals require brief cooking, but these hot cereals are less popular than cold, ready-to-eat cereals.
Prehistoric peoples ground whole grains and cooked them with water to form gruels and porridges similar to today's hot cereals. Cold cereals did not develop until the second half of the nineteenth century.
Ready-to-eat breakfast cereals were invented because of religious beliefs. The first step in this direction was taken by the American clergyman Sylvester Graham, who advocated a vegetarian diet. He used unsifted, coarsely ground flour to invent the Graham cracker in 1829. Influenced by Graham, Seventh-Day Adventists, who also believed in vegetarianism, founded the Western Health Reform Institute in Battle Creek, Michigan, in the 1860s. At this institute, later known as the Battle Creek Sanitarium, physician John Harvey Kellogg invented several grain-based meat substitutes.
In 1876 or 1877, Kellogg invented a food he called granola from wheat, oats, and corn that had been mixed, baked, and coarsely ground. In 1894, Kellogg and his brother W. K. Kellogg invented the first precooked flaked cereal. They cooked ground wheat into a dough, then flattened it between metal rollers and scraped it off with a knife. The resulting flakes were then cooked again and allowed to stand for several hours. This product was sold by mail order as Granose for 15 cents per 10-ounce (284 g) package.
Both W. K. Kellogg and C. W. Post, a patient at the sanitarium, founded businesses to sell such products as health foods. Their success led dozens of imitators to open factories in Battle Creek between 1900 and 1905. These businesses quickly failed, while Kellogg and Post still survive as thriving manufacturers of breakfast cereals.
Their success can be partially attributed to advertising campaigns, which transformed the image of their products from health foods to quick, convenient, and tasty breakfast foods. Another factor was the fact that Kellogg and Post both manufactured corn flakes, which turned out to be much more popular than wheat flakes. Breakfast cereals have continued to increase in popularity in the twentieth century. Ready-to-eat breakfast cereals are served in nine out of 10 American households.
The most important raw material in any breakfast cereal is grain. The grains most commonly used are corn, wheat, oats, rice, and barley. Some hot cereals, such as plain oatmeal, and a few cold cereals, such as plain shredded wheat, contain no other ingredients. Most breakfast cereals contain other ingredients, such as salt, yeast, sweeteners, flavoring agents, coloring agents, vitamins, minerals, and preservatives.
The sweeteners used in breakfast cereals include malt (obtained from barley), white sugar, brown sugar, and corn syrup. Some natural cereals are sweetened with concentrated fruit juice. A wide variety of flavors may be added to breakfast cereals, including chocolate, cinnamon and other spices, and fruit flavors. Other ingredients added to improve flavor include nuts, dried fruit, and marshmallows.
Vitamins and minerals are often added to breakfast cereals to replace those lost during cooking. The most important of these is vitamin B-i, 90 % of which is destroyed by heat. The antioxidants BHA and BHT are the preservatives most often added to breakfast cereals to prevent them from becoming stale and rancid.
Preparing the grain
- 1 Grain is received at the cereal factory, inspected, and cleaned. It may be used in the form of whole grains or it may require further processing. Often the whole grain is crushed between large metal rollers to remove the outer layer of bran. It may then be ground more finely into flour.
- 2 Whole grains or partial grains (such as corn grits) are mixed with flavoring agents, vitamins, minerals, sweeteners, salt, and water in a large rotating pressure cooker. The time, temperature, and speed of rotation vary with the type of grain being cooked.
3 The cooked grain is moved to a conveyor belt, which passes through a drying oven. Enough of the water remains in the cooked grain to result in a soft, solid mass which can be shaped as needed.
- 4 If flour is used instead of grains, it is cooked in a cooking extruder. This device consists of a long screw within a heated housing. The motion of the screw mixes the flour with water, flavorings, salt, sweeteners, vitamins, minerals, and sometimes food coloring. The screw moves this mixture through the extruder, cooking it as it moves along. At the end of the extruder, the cooked dough emerges as a ribbon. A rotating knife cuts the ribbon into pellets. These pellets are then processed in much the same way as cooked grains.
Making flaked cereals
- 5 The cooked grains are allowed to cool for several hours, stabilizing the moisture content of each grain. This process is known as tempering. The tempered grains are flattened between large metal rollers under tons of pressure. The resulting flakes are conveyed to ovens where they are tossed in a blast of very hot air to remove remaining moisture and to toast them to a desirable color and flavor. Instead of cooked grains, flakes may also be made from extruded pellets in a similar manner.
Making puffed cereals
- 6 Cereals may be puffed in ovens or in so-called "guns." Oven-puffed cereals are usually made from rice. The rice is cooked, cooled, and dried. It is then rolled between metal rollers like flaked cereals, but it is only partially flattened. This process is known as bumping. The bumped rice is dried again and placed in a very hot oven which causes it to swell.
- 7 Gun-puffed cereals may be made from rice or wheat. The rice grains require no pretreatment, but the wheat grains must be treated to partially remove the outer layer of bran. This may be done by abrading it off between grindstones, a process known as pearling. It may also be done by soaking the wheat grains in salt water. The salt water toughens the bran, which allows it to break off in large pieces during puffing. The grain is placed in the gun, a small vessel which can hold very hot steam and very high pressure. The gun is opened quickly to reduce the pressure suddenly, which puffs the grain. Extruded pellets can also be used to make gun-puffed cereals in the same way as grains.
Making shredded cereals
- 8 Shredded cereals are usually made from wheat. The wheat is cooked in boiling water to allow moisture to fully penetrate the grain. The cooked grain is cooled and allowed to temper. It is then rolled between two metal rollers. One roller is smooth and the other is grooved. A metal comb is positioned against the grooved roll with a tooth inside each groove. The cooked grain is shredded by the teeth of the comb and drops off the rollers in a continuous ribbon. A conveyor belt catches the ribbons from several pairs of rollers and piles them up in layers. The layers of shredded wheat are cut to the proper size, then baked to the desired color and dryness. Shredded cereals may also be made in a similar way from extruded pellets.
Making other cereals
- 9 Cereals can be made in a wide variety of special shapes (circles, letters of the alphabet, etc.) with a cooking extruder. A die is added to the end of the extruder which forms a ribbon of cooked dough with the desired cross-section shape. A rotating knife cuts the ribbon into small pieces with the proper shape. These shaped pieces of dough are processed in a manner similar to puffing. Instead of completely puffing, however, the pieces expand only partially in order to maintain the special shape.
- 10 Granolas and similar products are made by mixing grain (usually oats) and other ingredients (nuts, fruits, flavors, etc.) and cooking them on a conveyor belt which moves through an oven. The cooked mixture is then crumbled to the desired size. Hot cereals are made by processing the grain as necessary (rolling or cutting oats, cracking wheat, or milling corn into grits) and partly cooking it so the consumer can cook it quickly in hot water. Salt, sweeteners, flavors, and other ingredients may or may not be added to the partly cooked mixture.
- 11 After shaping, the cereal may be coated with vitamins, minerals, sweeteners, flavors such as fruit juices, food colors, or preservatives. Frosting is applied by spraying a thick, hot syrup of sugar on the cereal in a rotating drum. As it cools the syrup dries into a white layer of frosting.
- 12 Some cereals, such as shredded wheat, are fairly resistant to damage from moisture. They may be placed directly into cardboard boxes or in cardboard boxes lined with plastic. Most cereals must be packaged in airtight, waterproof plastic bags within cardboard boxes to protect them from spoiling.
- 13 An automated machine packages the cereal at a rate of about 40 boxes per minute. The box is assembled from a flat sheet of cardboard, which has been previously printed with the desired pattern for the outside of the box. The bottom and sides of the box are sealed with a strong glue. The bag is formed from moisture-proof plastic and inserted into the box. The cereal fills the bag and the bag is tightly sealed by heat. The top of the box is sealed with a weak glue which allows the consumer to open it easily. The completed boxes of cereal are packed into cartons which usually hold 12, 24, or 36 boxes and shipped to the retailer.
Every step in the manufacturing of breakfast cereal is carefully monitored for quality. Since cereal is a food intended for human consumption, sanitation is essential. The machines used are made from stainless steel, which can be thoroughly cleaned and sterilized with hot steam. Grain is inspected for any foreign matter when it arrives at the factory, when it is cooked, and when it is shaped.
To ensure proper cooking and shaping, the temperature and moisture content of the cereal is constantly monitored. The content of vitamins and minerals is measured to ensure accurate nutrition information. Filled packages are weighed to ensure that the contents of each box is consistent.
In order to label boxes with an accurate shelf life, the quality of stored cereal is tested over time. In order to be able to monitor freshness over a reasonable period of time, the cereals are subjected to higher than normal temperatures and humidities in order to speed up the spoiling process.
Breakfast cereal technology has advanced greatly since its origins in the late nineteenth century. The latest innovation in the industry is the twin-screw cooking extruder. The two rotating screws scrape each other clean as they rotate. This allows the dough to move more smoothly than in an extruder with only one screw. By using a twin-screw extruder, along with computers to precisely control temperature and pressure, cereals that usually require about 24 hours to make may be made in as little as 20 minutes.
Where to Learn More
Bruce, Scott, and Bill Crawford. Cerealizing America: The Unsweetened Story of American Breakfast Cereal. Faber and Faber, 1995.
Fast, Robert B., and Elwood F. Caldwell, eds. Breakfast Cereals and How They Are Made. American Association of Cereal Chemists, 1990.
Dworetzky, Tom. "The Churn of the Screw." Discover, May 1988, pp. 28-29.
Fast, R. B. "Breakfast Cereals: Processed Grains for Human Consumption." Cereal Foods World, March 1987, pp. 241-244.
Kellogg Company."How Kellogg's® Cereal is Made." December 4, 1996. http://kelloggs.com/booth/cereal.html (July 9, 1997).
ce·re·al / ˈsi(ə)rēəl/ • n. a grain used for food, such as wheat, oats, or corn. ∎ (usu. cereals) a grass producing such grain, grown as an agricultural crop: [as adj.] cereal crops. ∎ a breakfast food made from roasted grain, typically eaten with milk: a bowl of cereal| [as adj.] a cereal box.