Wild peanuts originated in Bolivia and northeastern Argentina. The cultivated species, Arachis hypogaea, was grown by Indians in pre-Columbian times. The peanut plant is a vinelike plant whose flowerstalks wither and bow to the ground after fertilization, burying the young pods, which come to maturity underground.
Peanuts were introduced to the United States from Africa, but were not considered a staple crop until the 1890s, when they were promoted as a replacement for the cotton crop destroyed by the boll weevil.
The three types of domestic peanuts are the Virginia, Spanish, and Runner-type peanuts. It is mostly the Runner-type peanuts, grown in Alabama, Florida, and Georgia, that are used in the manufacture of peanut butter. While Runner peanuts offer a higher yield, they also require more moisture than the Spanish or Virginia peanuts.
Around the end of the seventeenth century, Haitians made peanut butter by using a heavy wood mortar and a wood pestle with a metal cap. The mortar—featuring a metal bottom and weighing about 20 pounds—and the 5-pound pestle were used to pound the peanuts into a paste. During the nineteenth century in the United States, shelled, roasted peanuts were chopped or pounded into a creamy paste in a cloth bag and eaten fresh. American botanist and inventor George Washington Carver experimented with soybeans, sweet potatoes, and other crops, eventually deriving 300 products from the peanut alone—among the most notable was peanut butter.
A physician in St. Louis, Missouri started manufacturing peanut butter commercially in 1890. Featured at the St. Louis World's Fair as a health food, peanut butter was recommended for infants and invalids because of its high nutritional value. Sanitariums, particularly one in Battle Creek, Michigan, used it for their patients because of its high protein content.
Around 1925, peanut butter was sold from an open tub, with half an inch of oil on the surface. While the paste was sticky and produced considerable thirst, consumers were ready for such an economical and nutritious staple.
Realizing that the financial rewards from pig feed were beginning to dwindle, farmers began investing in the new cash crop. Thus, with increased harvest and availability of peanuts, the development and production of peanut butter grew. Most recently, peanut butter has been used primarily as a sandwich spread, although it also appears in prepared dishes and confections.
Originally, the process of peanut butter manufacturing was entirely manual. Until about 1920, the peanut farmer shelled the seed by hand, cultivated by hand hoeing about four times, and plowed with a single furrow plow, also four times. The farmer dug the vines with a single row plow, manually stacked the vines in the field for drying, and then hand-picked the nuts or beat them from the vines. A mule, a plow, and two hoes were all that was needed as far as peanut cultivation equipment was concerned. To produce peanut butter, small batches of peanuts were roasted, blanched, and ground as needed for sale or consumption. Salt and/or sugar was added upon request, and the product was eaten fresh. Mechanized cultivation and harvesting increased the yield of the harvest. Milling plants became larger, and consumption soared.
The peanut, rich in fat, protein, vitamin B, phosphorus, and iron, has significant food value. In its final form, peanut butter consists of about 90 to 95 percent carefully selected, blanched, dry-roasted peanuts, ground to a size to pass through a 200-mesh screen. To improve smoothness, spreadability and flavor, other ingredients are added, including include salt (1.5 percent), hydrogenated vegetable oil (0.125 percent), dextrose (2 percent), and corn syrup or honey (2 to 4 percent). To enhance peanut butter's nutritive value, ascorbic acid and yeast are also added. The amounts of other ingredients can vary as long as they do not add up to more than 10 percent of the peanut butter. Peanut butter contains 50 to 52 percent fat, 28 to 29 percent protein, 2 to 5 percent carbohydrate, and 1 to 2 percent moisture.
Planting and harvesting peanuts
- 1 Peanuts are planted in April or May, depending upon the climate. The peanut emerges as a plant followed by a yellow flower. After blooming and then wilting, the flower bends over and penetrates the soil. The peanut is formed underground. Peanuts are harvested beginning in late August, but mostly in September and October, during clear weather, when the soil is dry enough so it will not adhere to the stems and pods. The peanuts are removed from vines by portable, mechanical pickers and transported to a peanut sheller for mechanical drying.
- 2 Peanuts from the pickers are delivered to warehouses for cleaning. Blowers remove dust, sand, vines, stems, leaves, and empty shells. Screens, magnets, and size graders remove trash, metal, rocks, and clods. After the cleaning process, the peanuts weigh 10 to 20 percent less. The raw, cleaned peanuts are stored unshelled in silos or warehouses.
For George Washington Carver, peanuts were a means to several ends. Throughout his career, Carver searched for ways to make small Southern family farms, often African-American owned, self-sufficient. Carver's popularization of peanuts and peanut products was part of his effort to free small farmers from dependence on commercial products and debt. It was also part of his effort to wean farmers away from the annual production of soil-depleting staple crops like cotton and tobacco. Carver's list of peanut products—from peanut milk and makeup to paint and soap—represented a wide range of household activities.
Carver's interest in peanuts began in the mid-1910s, after he had pursued much research and education about other crops, especially sweet potatoes. A well-organized peanut industry lobby heard of Carver's work and capitalized on their mutual interest in the promotion of peanuts. Carver became the unofficial spokesman and publicist for the industry, especially after his 1921 appearance at tariffs hearings conducted by the U.S. House of Representatives' Ways and Means Committee. Facing alternatively bemused and hostile questioning from legislators, the African-American scientist eloquently and humorously explained the social, economic, and nutritional benefits of the domestic cultivation and consumption of peanuts. What evolved into a lunchtime favorite for kids was thrust into national prominence through one industry's search for growth and one man's search for economic independence for his people.
William S. Pretzer
Shelling and processing
- 3 Shelling consists of removing the shell (or hull) of peanuts with the least damage to the seed or kemels. The moisture of the unshelled peanuts is adjusted to avoid excessive brittleness of the shells and kernels and to reduce the amount of dust in the plant. The size-graded peanuts are passed between a series of rollers adjusted to the variety, size, and condition of the peanuts, where the peanuts are cracked. The cracked peanuts then repeatedly pass over screens, sleeves, blowers, magnets, and destoners, where they are shaken, gently tumbled, and air blown, until all the shells and other foreign material (rocks, mudballs, metal, shrivels) are removed.
- 4 The shelled peanuts are graded for size in a size grader. The peanuts are lifted and then oriented on the perforations of the size grader. The larger peanuts (the "overs") are sent to one trough, while the "troughs" are guided towards another trough. The peanuts are then graded for color, defects, spots, and broken skins.
- 5 The peanuts are shipped in large bulk containers or sacks to peanut butter manufacturers. (Inedible peanuts are diverted as oil stock in semibulk form.) To ensure proper size and grading, the truckloads transporting peanuts to peanut manufacturers are sampled mechanically. The sampler, testing two truckloads simultaneously, can quickly and accurately assess size and grading by examining 10 samples per truckload.
If edible peanuts need to be stored for more than 60 days, they are placed in refrigerated storage at 34 to 40 degrees Fahrenheit (2 to 6 degrees Celsius), where they may be held for as long as 25 months. Shelled, the remaining peanuts weigh 30 to 60 percent less, occupy 60 to 70 percent less space, and have a shelf life about 60 to 75 percent shorter than unshelled peanuts.
Making peanut butter
- 6 The peanut butter manufacturers first dry roast the peanuts. Dry roasting is done by either the batch or continuous method. In the batch method, peanuts are roasted in 400-pound lots in a revolving oven heated to about 800 degrees Fahrenheit (426.6 degrees Celsius). The peanuts are heated at 320 degrees Fahrenheit (160 degrees Celsius) and held at this temperature for 40 to 60 minutes to reach the exact degree of doneness. All the nuts in each batch must be uniformly roasted.
Large manufacturers prefer the continuous method, in which peanuts are fed from the hopper, roasted, cooled, ground into peanut butter and stabilized in one operation. This method is less labor-intensive, creates a more uniform roasting, and decreases spillage. Still, some operators believe that the best commercial peanut butter is obtained by using the batch method. Since peanut butter may call for a blending of peanuts, the batch method allows for the different varieties to be roasted separately. Furthermore, since peanuts frequently come in lots of different moisture content which may need special attention during roasting, the batch method can also meet these needs readily. The steps outlined below apply to peanut butter manufacturing that uses the batch method of roasting.
Cooling and blanching
- 7 A photometer indicates when the cooking is complete. At the exact time cooking is completed, the roasted peanuts are removed from heat as quickly as possible in order to stop cooking and produce a uniform product. The hot peanuts then pass from the roaster directly to a perforated metal cylinder (or blower-cooler vat), where a large volume of air is pulled through the mass by suction fans. The peanuts are brought to a temperature of 86 degrees Fahrenheit (30 degrees Celsius). Once cooled, the peanuts pass through a gravity separator that removes foreign materials.
- 8 The skins (or seed coats) are now removed with either heat or water. The heat blanching method has the advantage of removing the hearts of the peanuts, which contain a bitter principle.
- Heat blanching: Depending on the variety and degree of doneness desired, the peanuts are exposed to a temperature of 280 degrees Fahrenheit (137.7 degrees Celsius) for up to
20 minutes to loosen and crack the skins. After cooling, the peanuts are passed through the blancher in a continuous stream and subjected to a thorough but gentle rubbing between brushes or ribbed rubber belting. The skins are rubbed off, blown into porous bags, and the hearts are separated by screening.
Water blanching: A newer process than heat blanching, water blanching was introduced in 1949. While the kernels are not heated to destroy natural antioxidants, drying is necessary in this process and the hearts are retained. The first step is to arrange the kernels in troughs, then roll them between sharp stationary blades to slit the skins on opposite sides. The skins are removed as a spiral conveyor carries the kernels through a one-minute scalding water bath and then under an oscillating canvas-covered pad, which rubs off their skins. The blanched kernels are then dried for at least six hours by a current of 120 degrees Fahrenheit (48.8 degrees Celsius) air.
- 9 The blanched nuts are mechanically screened and inspected on a conveyor belt to remove scorched and rotten nuts or other undesirable matter. Light nuts are removed by blowers, discolored nuts by a high-speed electric color sorter, and metal parts by magnets.
- 10 Most of the devices used for grinding peanuts into butter are built so they can be adjusted over a wide range—permitting the variation in the quantity of peanuts ground per hour, the fineness of the product, and the amount of oil freed from the peanuts. Most grinding mills also have an automatic feed for peanuts and salt, and are easy to clean. To prevent overheating, grinding mills are cooled by a water jacket.
Peanut butter is usually made by two grinding operations. The first reduces the nuts to a medium grind and the second to a fine, smooth texture. For fine grinding, clearance between plates is about .032 inch (.08 centimeter). The second milling uses a very high-speed comminutor that has a combination cutting-shearing and attrition action and operates at 9600 rpm. This milling produces a very fine particle with a maximum size of less than 0.01 inch (.025 centimeter).
To make chunky peanut butter, peanut pieces approximately the size of one-eighth of a kernel are mixed with regular peanut butter, or incomplete grinding is used by removing a rib from the grinder.
At the same time the peanuts are fed into the grinder to be milled, about 2 percent salt, dextrose, and hydrogenated oil stabilizer are fed into the grinder in a continuous, horizontal operation, with about plus or minus 2 percent accuracy, and are thoroughly dispersed.
- 11 Peanuts are kept under constant pressure from the start to the finish of the grinding process to assure uniform grinding and to protect the product from air bubbles. A heavy screw feeds the peanuts into the grinder. This screw may also deliver the deaerated peanut butter into containers in a continuous stream under even pressure. From the grinder, the peanut butter goes to a stainless steel hopper, which serves as an intermediate mixing and storage point. The stabilized peanut butter is cooled in this rotating refrigerated cylinder (called a votator), from 170 to 120 degrees Fahrenheit (76.6 to 48.8 degrees Celsius) or less before it is packaged.
- 12 The stabilized peanut butter is automatically packed in jars, capped, and labeled. Since proper packaging is the main factor in reducing oxidation (without oxygen no oxidation can occur), manufacturers use vacuum packing. After it is put into final containers, the peanut butter is allowed to remain undisturbed until crystallization throughout the mass is completed. Jars are then placed in cartons and placed in product storage until ready to be shipped out to retail or institutional customers.
Quality control of peanut butter starts on the farm through harvesting and curing, and is then carried through the steps of shelling, storing, and manufacturing the product. All these steps are handled by machines. While complete mechanical harvesting, curing, and shelling may have some disadvantages, the end result is a brighter, cleaner, and more uniform peanut crop.
In the United States, strict quality control has been maintained on peanuts for many years with cooperation and approval from both the U.S. Department of Agriculture (USDA) and the Food and Drug Administration (FDA). Quality control is handled by the Peanut Administrative Committee, which is an arm of the USDA. Raw peanut responsibility rests with the Department of Agriculture. During and after manufacture, quality control is under the supervision of the FDA.
In its definition of peanut butter, the FDA stipulates that seasoning and stabilizing ingredients must not "exceed 10 percent of the weight of the finished food." Furthemore, the FDA states that "artificial flavorings, artificial sweeteners, chemical preservatives, added vitamins, and color additives are not suitable ingredients of peanut butter." A product that does not conform to the FDA's standards must be labeled "imitation peanut butter."
Peanut vines and leaves are used for feed for cattle, sheep, goats, horses, mules, and other livestock because of high nutritional value. Peanut shells accumulate in great quantities at shelling plants. They contain stems, peanut pops, immature nuts and dirt. These shells are used mainly for fuel for the boiler generating steam for making electricity to operate the shelling plant. Limited markets exist for peanut shells for roughage in cattle feed, poultry litter, and filler in artificial fire logs. Potential additional uses are pet litter, mushroom-growing medium, and floor-sweeping compounds.
In the United States and most of the 53 peanut-producing countries in the world, the production and consumption of peanuts, including peanut butter, is increasing. The quality of peanuts continues to improve to meet higher standards. The convenience peanut butter offers its users and its high nutritional value meet the demands of contemporary lifestyles.
The use of peanuts as food is being introduced to remote parts of the world by American ambassadors, missionaries and Peace Corps volunteers. Some developing countries, understanding that their food protein scarcity will not be solved through animal proteins alone, are interested in growing the protein-rich peanut crop.
Where To Learn More
Coyle, L. Patrick, Jr. The World Encyclopedia of Food. Facts on File, 1982.
Erlbach, Arlene. Peanut Butter. Lerner Publications, 1993.
Lapedes, Daniel, ed. McGraw Hill Encyclopedia of Food, 4th ed: Agriculture and Nutrition. McGraw-Hill, 1977.
Woodroof, Jasper Guy, ed. Peanuts: Production, Processing, Products. Avi Publishing Company, 1983.
Zisman, Honey. The Great American Peanut Butter Book: A Book of Recipes, Facts, Figures, and Fun. St. Martin's Press, 1985.
"The Nuttiest Peanut Butter." Consumer Reports. September, 1990, p. 588.
"PBTV." Environment. November, 1987, p. 23.
"Peanut Butter." How Products Are Made. . Encyclopedia.com. (November 11, 2018). https://www.encyclopedia.com/manufacturing/news-wires-white-papers-and-books/peanut-butter
"Peanut Butter." How Products Are Made. . Retrieved November 11, 2018 from Encyclopedia.com: https://www.encyclopedia.com/manufacturing/news-wires-white-papers-and-books/peanut-butter
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PEANUT BUTTER. Peanuts (Arachis hypogaea ), also widely called "groundnuts," originated between southern Bolivia and northern Argentina. In pre-Columbian times, they were found throughout Brazil, Peru, Mexico, and the Caribbean. Early in the sixteenth century, European explorers transported them to Africa and Asia. From the beginning, peanuts were ground into paste and used as a flavoring in soups, stews, and other dishes.
Through the slave trade, peanuts were introduced into the British North American colonies. Slaves grew peanuts in their gardens and introduced them into mainstream cookery. Hand-ground peanuts appeared as an ingredient in American recipes by the 1830s.
Ground peanuts were a minor product until popularized by John Harvey Kellogg, the vegetarian director of the Seventh-Day Adventist Sanitarium in Battle Creek, Michigan. In 1894 he created a process to make "nut butters," which were intended as a substitute for cow's butter and cream. Peanuts were the least expensive "nuts" available, and the product made from grinding them was promptly called peanut butter. It was served to members of America's elite who visited the sanitarium, and vegetarians began selling it in small batches. Kellogg's new culinary treat spread throughout the United States and, subsequently, the world. Kellogg decided not to patent the process for making peanut butter, but he did create the Sanitas Nut Food Company to sell his nut butters.
Peanut butter quickly became a fad among health food manufacturers in America. Vegetarians adopted it almost immediately, and recipes for making it appeared in vegetarian cookbooks beginning in 1899. Vegetarians employed peanut butter for many purposes, but particularly for making mock meats or meat substitutes that purportedly imitated the appearance and taste of such diverse products as chicken, veal cutlets, tenderloin steak, oysters, and meat loaf.
Mainstream Peanut Butter
Peanut butter quickly spread into the culinary mainstream and was employed as an ingredient in salad, fudge, biscuits, muffins, cookies, and breads. A major early use of peanut butter was for making sandwiches, which were initially flavored with a variety of ingredients, such as mayonnaise, cayenne, paprika, nasturtiums, cheese, watercress, meat, Worcestershire sauce, and cream cheese. Recipes for peanut butter sandwiches proliferated throughout the early twentieth century. The first known reference to combining jelly with peanut butter was published in 1901. During the early 1900s, peanut butter was considered a delicacy and, as such, it was served at New York's finest tearooms.
Commerce and Industry
Initially, peanut butter was made by grinding a few nuts at a time in a mortar and pestle. As this was a slow and difficult process, it was unlikely that peanut butter would ever have become a major culinary product. It was at this point that technological innovation intervened, and converted a food fad into an industry. Commercial peanut butter made its debut in 1896. Before the development of special grinders, the peanuts were ground in adapted meat grinders. The peanut butter was manufactured in small quantities by individuals and sold from house to house; then small factories sprang up, and peanut butter became a familiar article on grocers' shelves. The first recorded peanut butter trademark was granted to the Atlantic Peanut Refinery in Philadelphia in December 1898. The recipe consisted only of ground peanuts with salt added. By 1899, an estimated two million pounds of peanut butter were manufactured in the United States. The largest producers were located in the South and the West. By 1929, there was hardly a city that did not have one or more peanut butter factories, and its consumption during the next five or six years equaled that of all preceding years combined.
Peanut butter sandwiches moved down the class structure as the price of peanut butter declined. After the invention of sliced bread in the 1920s, children could make their own sandwiches without using a sharp knife. The combination of these two factors helped make peanut butter sandwiches one of the top children's meals in America. Beginning in the 1920s, manufacturers lobbied school cafeterias to buy inexpensive peanut butter. Its flavor was liked by children, and minimum time and equipment were required to prepare it. However, peanut allergies among children have recently been on the rise, and peanuts and peanut products have been banned from some schools.
Today, three major peanut butter manufacturers dominate the market: Skippy, created by Joseph L. Rosefield of Alameda, California (first produced in 1932); Peter Pan peanut butter, manufactured by the E. K. Pond Company (Pond, a subsidiary of Swift & Co., began making peanut butter in 1926); and Procter & Gamble's Jif (first produced in 1958), whose plant in Lexington, Kentucky, is the largest peanut-butter-producing facility in the world.
Peanut Butter as an American Icon
Peanut butter was initially considered a health and vegetarian food, but it quickly became a major mainstream staple, a mass-produced commodity sold in almost every grocery store in America. It was employed on virtually every type of food from soups, salads, sauces, and main courses to desserts and snacks of every description. Few other products in American culinary history have achieved such influence in so many ways in such a short period of time, and peanut butter has remained a staple food in America ever since.
Peanut butter has been employed in a number of other commercial products—cakes, confections, cereals, and many snack foods—the most successful being in the manufacture of chocolate bars. In 1928 H. B. Reese Candy Company produced a chocolate-covered peanut butter cup, which subsequently became known as "Reese's Peanut Butter Cup." Two years later, Frank and Ethel Mars introduced the "Snickers Bar," a combination of peanut butter nougat, peanuts, and caramel encased in milk chocolate. Snickers quickly became America's most popular candy bar, a position it has held ever since. Chocolate and peanut butter are combined in some of America's best-selling chocolate bars, including Snickers and Reese's Peanut Butter Cup.
Peanut butter cookbooks have been regularly published since William Kaufman's "I Love Peanut Butter" Cookbook was published in 1975. The Adult Peanut Butter Lovers' Fan Club currently counts over sixty thousand members. Today, Americans consume annually about 857 million pounds of peanut butter, or 3.36 pounds per person. It can be found in 83 percent of American households. Peanut butter is also consumed in Saudi Arabia, Canada, Japan, Korea, and Western Europe.
See also Kellogg, John Harvey ; Legumes ; Nuts ; Oil ; Snacks .
Frank, Dorothy. The Peanut Cookbook. New York: Clarkson Potter, 1976.
Hoffman, Mable. The Peanut Butter Cookbook. New York: HP Books, 1996.
Holmes, Leila B. Plain Georgia Cookin': 100 Peanut Recipes. Thomasville, Ga.: Barnes Printing, 1977.
Kaufman, William. The "I Love Peanut Butter" Cookbook. Garden City, N.Y.: Doubleday, 1965.
Kolpas, Norman. The Big Little Peanut Butter Cookbook. Chicago: NTC/Contemporary Books, 1990.
Smith, Andrew F. "Peanut Butter: A Vegetarian Food that Went Awry." Petits Propos Culinaires 65 (September 2000): 60–72.
Smith, Andrew F. Peanuts: The Illustrious History of the Goober Pea. Urbana: University of Illinois Press, 2002.
Woodroof, Jasper Guy, ed. Peanuts: Production, Processing, Products. 3d ed. Westport, Conn.: AVI Publishing, 1984.
Zisman, Larry, and Honey Zisman. The Great American Peanut Butter Book. New York: St. Martin's, 1985.
Andrew F. Smith
"Peanut Butter." Encyclopedia of Food and Culture. . Encyclopedia.com. (November 11, 2018). https://www.encyclopedia.com/food/encyclopedias-almanacs-transcripts-and-maps/peanut-butter
"Peanut Butter." Encyclopedia of Food and Culture. . Retrieved November 11, 2018 from Encyclopedia.com: https://www.encyclopedia.com/food/encyclopedias-almanacs-transcripts-and-maps/peanut-butter
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"peanut butter." A Dictionary of Food and Nutrition. . Encyclopedia.com. (November 11, 2018). https://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/peanut-butter
"peanut butter." A Dictionary of Food and Nutrition. . Retrieved November 11, 2018 from Encyclopedia.com: https://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/peanut-butter
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pea·nut but·ter • n. a paste of ground roasted peanuts, usually eaten spread on bread.
"peanut butter." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. (November 11, 2018). https://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/peanut-butter
"peanut butter." The Oxford Pocket Dictionary of Current English. . Retrieved November 11, 2018 from Encyclopedia.com: https://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/peanut-butter