Deep Frying

cooking · food science · heat

Oil cooks fast. Oil conducts heat much faster than water or air, so food cooked in deep oil gets done quickly. All sides of the food cook at the same time because it is completely surrounded by the hot oil.

Submerged in oil. Unlike regular frying in a pan where food sits in a little bit of oil, deep frying means the entire piece of food is covered and dipped into a big pot or fryer filled with hot oil. This is what makes it deep frying.

Really hot oil. The oil gets heated to very high temperatures, which creates that golden, crispy outside layer on foods like french fries and fried chicken. The heat also seals in the food's moisture so the inside stays tender.

Different fryer types. Home cooks use simple deep fryers or pots of oil, but big food factories use special pressure fryers or vacuum fryers to cook huge batches of food all at once. Each type of fryer works best for different foods.

Oil choices matter. Long ago, people used lard (animal fat) for deep frying, but today most kitchens use vegetable oil because it is easier to get and can handle the high heat needed for cooking.