Deep frying (also referred to as deep fat frying) is a cooking method in which food is submerged in hot fat, most commonly oil, rather than the shallow oil used in conventional frying, done in a frying pan. Normally, a deep fryer or chip pan is used for this; industrially, a pressure fryer or vacuum fryer may be used. Deep frying may also be performed using oil that is heated in a pot. Deep frying is classified as hot-fat cooking method. Typically, deep frying cooks foods quickly: all sides of a food are cooked simultaneously as oil has a high rate of heat conduction.
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 a few European and Arabian countries before other countries adopted the practice.
Deep frying is popular worldwide, with deep-fried foods accounting for a large portion of global caloric consumption. Many foods are deep-fried and cultures surrounding deep frying have developed, most notably in the Southern United States, where many events dedicated to deep frying food and non-edible items are held.
Although the nouns "deep-fried", "deep-frying", and the verb "deep-fry" were not documented until 1916, 1932, and 1933 (respectively); the practice of deep frying food has been around much longer. One of the earliest known practices of deep frying came from the Egyptians in the 5th millennium BCE. Later developments included the Greeks deep frying food in olive oil in the 5th century BCE. In the 1st century CE, a Roman cookbook, Apicius, appears to list the ancient Romans' first use of deep frying to prepare Pullum Frontonianum, a chicken dish. The practice of deep frying spread to other parts of Europe and Arabia in the following centuries. 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.Falafel arrived in the Middle East from population migrations from Egypt as soon as the 14th century. The deep frying of food in Japan was likely introduced by Portuguese the 16th century. Evidence of potato frying can be found as early as the late 17th century in Europe.