FRYING. Fried foods, though widely considered indelicate, are also among the most ephemeral. Regarding fried foods, a Chinese proverb states: It is better that your guests wait for their meal, than that the meal wait for the guests. Fried dishes cannot wait, and if allowed to stand, rising interior steam causes them to lose their crisp exterior and, thereby, their character.
Frying is a means of heat transfer that works by both conduction (direct contact) and convection (the natural movement of molecules in a fluid). Like broiling, boiling, and baking, frying is a method of cooking, but unlike water-based cooking (boiling, braising, or steaming), frying uses dry heat. Oil wicks moisture away from food surfaces. Because oil heats to a higher temperature than water, frying is faster than boiling, and fried surfaces, rather than becoming soft as they do when boiled, broiled, or steamed, coagulate. The resulting fried food is incomparably tasty, crisp, and beautiful. Frying comprises not only deep-frying and pan-frying, but also the cooking method used to prepare common foods such as pancakes and fried eggs as well as less-known foods such as the Indian dish dalia uppma, an herbed bulgur with fried vegetables. Most, but not all, of the world's cultures have practiced frying.
Some fried foods are so popular that they can be identified as cultural stereotypes. American french fries and Middle Eastern falafel (chickpea or fava bean fritters) are examples. Native Americans of the Southwest are known for fry bread, and corn dogs are associated with New York's Coney Island. The American South has southern fried chicken, while in Asia, sweet potatoes are fried and served from vendors' carts. In Mexico, on the zócalo (the central square), vendors working from carts sell churros, a deep-fried pastry.
Advantages and Disadvantages
Through the ages, frying has remained popular because it adds an outside layer of flavor and crunch to soft foods, such as eggplant and okra. In addition, frying cooks and browns beautifully. It adds texture and yields the smooth and taste-imparting feel that comes only from various oils and fats.
On the negative side, the process of deep-fat frying is dangerous and requires special equipment and controlled environments. To avoid the overflow of hot oil from the pan, large temperature-controlled deep fryers are used, and these pans are filled only about one-third of their depth with oil. In addition, to maintain the desired high temperature, deep fryers are not filled with food, but rather, food is fried in small batches. Moist foods are not placed in hot oil because they cause boiling and popping, which can be dangerous. To avoid burns and fires protective gloves and clothing, long-handled utensils, as well as fire extinguishers and baking soda, are used. Unlike water, oil can catch on fire, and oil fires spread quickly. If a pan of oil catches fire, the pan is covered with a lid, doused with salt, or sprayed with a fire extinguisher. A stream of water is not effective in dousing an oil fire.
The use of oils and fats has also become a health concern. Those who support frying claim that with fast, clean frying, only a small amount of oil remains on the food, and certain oils and fats are healthier than others. Olive oil and canola oil, monounsaturated vegetable oils, are recommended for human consumption, while saturated oils, such as palm and coconut oil, or saturated fats, such as butter or lard, are not recommended. Canola oil is considered good for one's health because of its ratio of linoleic acid (an omega-6 fatty acid) to linolenic acid (an omega-3). A balance of omega-6s and omega-3s is an asset to health, with other oils often lacking the omega-3s. Canola oil offers the best balance for omega-3 and omega-6 fatty acids.
Methods of Frying and Equipment
Frying methods include sautéing, stir-frying, pan-frying, and deep-fat frying. These styles of frying form a continuum based on the amount of oil used, with sautéing using the least oil and deep-fat frying using the most.
Each of the principal frying methods is associated with a particular pan. Pan-frying is practiced in stainless steel, aluminum, and heavy cast-iron skillets, all with sloping sides. To sauté, there exists a French sauterne or sauté pan, which is wide like a skillet, but has low and straight sides. Deep-frying occurs in the deep fryer or wok, with either a fry basket insert, the long-handled slotted skimmer, or, as in China, the spider (small basket) attached to a long bamboo handle. Deep-frying thermometers are used to help the cook maintain a constant temperature. Finally, when fried foods, such as bacon or potato chips, are removed from the oil, they are placed on drip racks or paper towels. Deep-fat fryers are available in many sizes, from large multigallon commercial vats to small personal fryers that hold two or three cups of oil.
Other frying pans, too, are associated with specific foods. In crêpe pans, thin pancakes are cooked in a style associated with classical French cooking. Round or oval omelet pans are used to fry omelets. Heavy cast-iron chicken fryers are deep pans that include nippled lids that allow moisture to drip back onto the frying chicken. Restaurant kitchens often fry eggs, pancakes, sausages, and sandwiches on large steel frying surfaces called griddles, but home cooks can purchase small, hand-held griddle pans for the same purpose.
With a wok, many foods are stir-fried in the style of several Asian traditions. Woks are available as self-contained electric units or as wide, deeply sloped circular pans that fit over a gas flame. They are often sold with lids so that foods can be steamed for part of the cooking time. Before vegetables, seafood, poultry, or meats are added to the stir-fry pan, a small amount of oil is heated to a high temperature. In China, where stir-frying is an ancient tradition as well as a modern art form, small pieces of food are placed in a large pan over intense heat, and they are stirred quickly as they cook.
Oils and Fats
Frying fats may be solid or liquid. In selecting an oil or fat, the oil should be fresh and clean. Its flavor should not overpower the food being cooked, and monounsaturated vegetable oils have been recommended for presumed health reasons. Solid vegetable shortenings contain emulsifiers, which make them good for use in cakes, but poor for frying. The emulsifiers lower smoke points to about 370°F. Margarine and butter spreads are also not recommended for frying as they contain a variety of fats and even water.
Butter is a special case, as it adds much-valued flavor to many foods. Butter, however, until it is clarified, contains milk solids and burns at about 250°F. When the solids are removed by clarification, butter is an improved medium for frying, and its smoke point rises to 375°F. In India, both solids and water are removed from butter, and the resulting ghee or usli ghee is used for pan-and deep-frying. Lard as well as chicken, duck, and goose fats are also used successfully for frying. They impart excellent flavor but prompt health concerns among some researchers.
The purest flavor and safest frying are achieved when oil and fats are used one time. If frying is continuous for long periods, the oil requires changing, as it begins to darken or deteriorate. If frying oil is too hot, it will burn or break down, and if too cold, or less than about 300°F, the food being fried will absorb too much oil and become greasy.
Frying is faster than boiling or steaming because oils get hotter than do water or steam. Smoke points, however, limit maximum possible frying temperatures. Oil is too hot when it reaches the smoke point, the temperature at which the oil starts to smoke, deteriorate, and burn. Too much heat causes gaseous fumes and chemically active, free fatty acids to negatively impact flavor. Maintaining the optimum temperature can be challenging, as each time oil is used, it picks up food particles, breaks down, and loses its ability to absorb heat. In addition, over-used or rancid oil smells and tastes bad.
Oils deteriorate by oxidation or contact with the air, and heat speeds this process. Thus, in storage and cooking, contact with air should be minimized. For deep-frying, a deep and narrow pan is better than a shallow, wide one because it allows for less air contact.
Suitable frying oils have high smoke points; the higher the smoke point, the faster the cooking. Depending on the oil, smoke points range from a low 250°F to a high 520°F. For example, while water boils at 212°F, the favored frying oils such as olive, peanut, and canola have smoke points ranging from 410°F to 437°F and are best heated to 365°F. This temperature cooks food quickly yet does not burn these oils.
During the British colonial period, frying spread from Europe to the Americas and Africa. American colonists adapted frying with great frenzy, and in a Harper's magazine story of 1866, Americans were said to be eating, "Fried ham, fried eggs, fried liver, fried steak, fried fish, fried oysters, fried potatoes, and last, but not least, fried hash." These preparations, as well as doughnuts, pancakes, and fritters, were served "morning, noon, and night," according to the magazine contributor, who thought that Americans consumed too much fried food.
Due to a lack of either resources or technology, frying was absent from some ancient cultures. Early European scholars writing about the food among the original inhabitants of the New World could not believe that these cultures did not have oil and did not fry. Because these cultures did not have use of rotary motion, they could not reduce their quantities of peanuts or other seeds to oil. While European cultures used round wheels, Native Americans ground maize and other grains with a to-andfro motion. After Europeans arrived, some Native Americans found the unfamiliar cooking oils and fats repulsive. In modern Latin America, with some exceptions, such as street fair food, fried tortillas, and pescado frito (fried fish), frying is not among the significant methods of cooking.
Foods, especially meats, were fried during the first century C.E. in many cultures around the Mediterranean. In Rome the term "frying," or frigere, had two meanings, first, the toasting of grains in a dry skillet, and second, cooking in oil. From the eighth to the fifteenth century, fats and frying played an essential role in Arab cooking. Sheep tail fat was a frying delicacy; books from this region and period tell how to extract, clarify, perfume, color, and store this fat, which was used to finish-fry boiled meats. During the same period, Andalusia, Maghreb, and Syria were known for their olive oil, which was exported to Iraq and Egypt. The modern practice of browning, or lightly searing, meats through frying before stewing is described in Arab literature, also from this period. The result of this practice is that outer surfaces are slightly burned, and this enhances the flavor of stews.
Sautéing and Pan-frying
The first step in preparing an Indian curry is to heat a small amount of oil and then quickly sauté a variety of herbs and spices. Similarly, Chinese cooks pre-heat oil, often with garlic, before stir-frying. High heat releases flavor and aroma. Stew meats, for example, are often pan-fried to seal juices and develop surface flavor. In French and American kitchens, sautéing is used to quickly fry vegetables and other foods with little oil.
Pan-frying is the use of a shallow, slope-sided frying pan or skillet to cook in oil. Like deep-frying, it depends on conduction and convection. In pan-frying, a layer of oil has four functions: it lubricates the surface; increases contact between the food and the pan; reduces cooking time; and increases flavor and color.
When frying battered fish or chicken, the oil covers the pan but not the food, but when frying pancakes, the oil is but a thin film to keep the batter from sticking. Asian cooks fry rice with all kinds of meats, seafood, vegetables, and nuts. Chinese fried rice is pan-fried in a skillet with very little oil, perhaps one tablespoon per cup of rice. The challenge of pan-frying thick items such as chicken parts is to cook to the center without burning the surface. The Chinese have effectively solved this problem by slicing foods thin enough so the surface and interior cook in the same time.
With deep-fat frying, foods are submerged in hot oil. Because of the expense of the oil or because of the difficulty of this method, deep-frying is associated with celebrations, festivals, and street carnivals. American street fair vendors commonly serve deep-fried corn dogs, elephant ears, and funnel cakes. Deep-fat frying, also called deep-frying, is popular for breads, like southern cornmeal hush puppies, as well as for battered food, such as seafood or vegetables. Some food categories such as tempura, croquettes, and fritters are always deep-fried.
In India, poori breads are deep-fried, while paratha breads of whole wheat, potato, pea, chickpea, and corn are both griddle-and shallow-fried. Poori bread is a puffed up whole-wheat bread, much like chapati, another Indian bread that rather than being deep-fried is fried or "baked" on a griddle.
While European and Western cooks deep-fry with a single frying, the Chinese deep-fry in stages. After being marinated, foods are then deep-fried at a low temperature, maybe 290°F, and later finish-fried at a high temperature, 365°F to 385°F. This staged cooking increases crispness and color.
Batters reduce surface moisture, and a dryer surface reduces initial boiling. In addition, batters add color, flavor, and texture to many deep-fat fried foods, with green tomatoes, eggplant, okra, and even ice cream being examples of foods that are battered before they are fried. A meunière is a thin, light breading, or flour dusting, often used on fish and popular in traditional French kitchens. But batters can also be thick, as in the case of double, triple, or breaded coatings used for fried fish and chicken.
In summary, frying is quite expensive, somewhat controversial, almost universal, and very pleasing. The quick removal of moisture from food surfaces through the wicking effect of hot oil is a cooking method that will remain popular in homes and restaurants and at public events.
See also Baking; Boiling; Broiling; Butter; Fats; Oil; Roasting; Stew; United States: The South; Utensils, Cooking.
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Mark F. Sohn