A deep fryer is a cooking appliance that provides a relatively safe way to submerge items of food in hot oil without being burned. Cooking with large amounts of oil can be very dangerous, as oil tends to splatter and can cause serious burns. Oil is often heated to temperatures approaching 280 to 400 degrees Fahrenheit, or 140 to 200 degrees Celsius. Rather than heat oil in a pot, it is recommended that people use a deep fryer to cook such foods.

A deep fryer consists of a large tank, into which the oil is poured, and a basket, which can be safely submerged into the oil after it has gotten hot enough. There are both commercial and home models of the deep fryer. The commercial deep fryer is very common in fast food restaurants, and is used to prepare French fries and other foods. A deep fryer is not one of the most common home cooking appliances, but it can be used to prepare delicious meals at home.

When using a deep fryer, the oil you cook with can be reused multiple times, often as many as ten or fifteen. Either corn oil or vegetable oil are good for use in a deep fryer; olive oil is generally too expensive to use, since a deep fryer requires quite a bit of oil. If you like, you can even keep the oil in the deep fryer, as long as it will be kept in a cool place and you plan to reuse the oil within several weeks.

There are many types of food that can be delicious when prepared in a deep fryer. You can deep fry French fries, sweet potato fries, mozzarella sticks, fried chicken, onion rings, tater tots, chicken nuggets, and many other types of food. Celebrities including Martha Stewart even claim that the best way to cook a Thanksgiving turkey is to cook it in the deep fryer. In deep frying, though the food is submerged in oil, it does not typically become overly greasy. Instead, the oil only penetrates the food's surface, making it crispy, while steaming the inside. However, foods cooked in a deep fryer often have many calories, because the outside or breading of the food retains a lot of the oil from cooking.

One of the most famous dishes made in a deep fryer is the deep-fried Twinkie, a Scottish invention in which a Twinkie snack bar is dipped in batter and deep fried, so that the inside melts and the outside is crispy. This Scottish invention is very tasty, but extremely unhealthy. You can now find it at many amusement parks and other places throughout the world, along with deep-fried Oreos and other deep-fried candy bars.