Deep frying

Lore & Background

The term 'deep frying' and many modern deep-fried foods were not invented until the 19th century, but the practice has been around for millennia. Early records and cookbooks suggest that the practice began in certain European countries before other countries adopted the practice. Deep-fried dough was eaten as early as the late 2nd millennium BC in Canaan.

Frying food in olive oil is attested in Classical Greece from about the 5th century BC. The 5th century AD Roman cookbook Apicius offers a recipe for deep fried chicken in a cream sauce fried in olive oil. Sanskrit texts such as the 12th century Manasollasa mention snacks like malpua and vataka being submerged and fried in ghee. Deep-fried foods such as funnel cakes arrived in northern Europe by the 13th century, and deep-fried fish recipes have been found in cookbooks in Spain and Portugal at around the same time.

In 1860, Joseph Malin combined deep fried fish with chips to open the first fish and chip shop in London. Modern deep frying in the United States began in the 19th century with the growing popularity of cast iron, particularly around the American South which led to the development of many modern deep-fried dishes. Doughnuts were invented in the mid-18th century, with foods such as onion rings, deep-fried turkey, and corn dogs all being invented in the early 20th century.

Reader's Guide

Deep frying food is defined as a process where food is submerged in hot oil at temperatures typically between 350 F and 375 F, but deep frying oil can reach temperatures of over 400 °F (205 °C). One common method for preparing food for deep frying involves adding multiple layers of batter around the food, such as cornmeal, flour, or tempura; breadcrumbs may also be used. While most foods need batter coatings for protection, it is not as necessary for cooked noodles and potatoes because their high starch content enables them to hold more moisture and not shrink. Foods such as French fries can be battered if extra crispiness is desired.

Meats are sometimes partially cooked before deep frying to ensure that they are done inside while keeping their juiciness. When performed properly, deep frying does not make food excessively greasy, because the moisture in the food repels the oil. The hot oil heats the water within the food, steaming it; oil cannot go against the direction of this powerful flow because the water vapor pushes the bubbles toward the surface.

As long as the oil is hot enough and the food is not immersed in the oil for too long, oil penetration will be confined to the outer surface. Foods deep-fried at proper temperatures typically absorb less than per of oil used. This oil absorption rate is around the same as occurs with shallow frying. However, if the food is cooked in the oil for too long, much of the water will be lost and the oil will begin to penetrate the food.

The correct frying temperature depends on the thickness and type of food, but in most cases it lies between 350 - 375 F. An informal test for a temperature close to this range involves adding a tiny amount of flour into the oil and watching to see if it sizzles without immediately burning. A second test involves adding one piece of food to deep fry and watching it sink somewhat and rise back up. Sinking without resurfacing indicates that the oil is too cold; not sinking at all indicates that the oil is too hot.

It is recommended that deep fryers be cleaned often to prevent contamination. The process of cooking with oil can also contaminate nearby surfaces as oil may splatter on adjacent areas. Oil vapors can also condense on more distant surfaces such as walls and ceilings. Supplies such as dish detergent and baking soda can effectively clean affected surfaces.

Did You Know?

• Deep frying is popular worldwide, with deep-fried foods accounting for a large portion of global caloric consumption.