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.
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
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
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.
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.
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.
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.
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.
— Eva Sideman