8.4 Frying: shallow and deep

How much fat

All frying works on the same idea. What changes is the depth of fat. Sautéing and stir-frying use a thin film. Pan-frying uses about half an inch of oil. Deep-frying uses enough oil to cover the food completely.

Why frying is fast

Fat carries heat into food much better than air or water. So frying is far quicker than baking or boiling. It also gives food a crisp crust and a rich taste. The big drawback is health. Deep-fried food comes out holding between 5 and 40 percent of its weight in oil.

What happens in the hot oil

Frying oil is usually heated to between 350 and 425°F. When food goes in, it fizzes hard. The oil is not boiling. The bubbles are steam bursting out of the food, because water boils at 212°F and the oil may be twice as hot.

That steam does two useful jobs. It pushes the oil back, so oil stays at the surface. It also cools the oil right around the food. This gives the center time to heat through and flavors time to form, before the outside burns.

As steam leaves, the surface dries into a crisp crust. Then heat moves faster to the center. Watch the bubbles. When they become fewer and calmer, the food is almost done. Lift it out when it reaches the golden brown you want, then drain it, season it and serve it. For deep-fried chicken, check with an instant-read thermometer that it has reached 165°F.

The browning on the outside of deep-fried food is an example of the Maillard reaction.

Greasy food and soggy food

Poor draining and a long wait before serving also make food greasy. Batches can cause that wait. A wire rack set in a sheet pan drains food better than paper towel on a flat surface, because the dripping fat stays away from the food. Keep finished food in a 200°F oven until it is served. While it stays hot and steaming, oil is slow to soak in.

Coated food goes soggy as it cools. The moisture trapped between the coating and the food turns to water drops instead of steam, and the crust softens from the inside.

Batters and breadings

A coating guards the food from the fierce action at its surface. It also keeps moisture in and adds taste and texture.

• Batter gives a smooth, crisp, often delicate crust. Food is sometimes floured before it is battered. High-gluten flour makes a chewy crust. Gluten-free flour, such as rice flour, makes a very thin, very crisp one. Egg or sugar in a batter makes the crust darker.
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• Batter has less surface area than most breadings, so it takes up less oil. It protects delicate food best, which is why fish is so often battered. Louisiana-style fried fish is seasoned and then coated in corn flour or cornmeal.
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• Breading gives a crunchy, textured crust. Fine crumbs take up less oil than coarse ones, but they go soggy more easily. For an extra-crisp coating, use large pieces that are already crisp, like panko or crushed cornflakes. Panko is Japanese-style breadcrumbs.
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• The usual breading order has three steps. First, flour, sometimes seasoned. Next, a wet dip: egg wash, buttermilk or whipped egg whites. Last, the outer coat: panko, cracker crumbs, white flour or corn flour.
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• Starchy foods such as potatoes, plantains and yucca root need no coating. They form a protective skin of their own in the fryer.

Deep-fryer safety

Follow these rules for deep-frying.

• A pan of oil on the stove goes on a back burner. An electric fryer goes where nobody can catch its cord.
• Keep a lid close by. Use it only if the oil catches fire.
• Put a thermometer in the oil and heat the oil to the temperature the recipe asks for.
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• Move food in and out with a slotted spoon, tongs or a basket. Never crowd the oil: one layer of food at most.
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• Let the oil drip off over the pot before the food goes onto paper towel.
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• Never walk away from heating oil. If it catches fire, turn the burner off and cover the pot with the lid. Smother any other flames with a wet towel, a fire blanket or a fire extinguisher. Never throw water on burning oil.
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• When you are done, let the oil cool, then strain it through two or three layers of cheesecloth.
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Oil also wears out. Rancidity is the off flavor that develops as oil oxidizes and breaks down.

Frying temperatures in practice

Recipes for these deep-fried foods use oil between 330 and 375°F:

Two terms come up with fried foods. A fritter is chopped food coated in batter and deep-fried. A croquette is a mixture of meat and vegetables bound with white sauce, then coated and deep-fried.

A good deep-fried product

• Appearance: a fairly smooth outside, an even golden brown. The inside is cooked all the way through and has taken up little oil.
• Texture: a crust that is crisp or tender, never soggy.
• Flavor: no greasy taste and no greasy feel in the mouth.