Deep-frying is the technique of submerging food in hot oil and cooking it until a crisp, golden outer layer forms but leaving a moist, tender interior. When food is dropped into very hot oil, steam escapes from the interior, shooting outward into the oil in tiny bubbles. This is why fried foods begin to fizz as they hit the hot oil. The high temperature of the oil forms a crust that immediately acts as a barrier to limit the amount of oil that is absorbed by the food, while the heat from the oil continues to cook the inside, causing starches and fibers to soften and proteins to denature. Herein lies the appeal of the perfect fried food: the contrast of crunch and softness that you find in a golden French fry, well-executed vegetable tempura, or crispy fried chicken.
Deep-frying is not complicated, but there are rules that are worth sticking with in order to get that perfect golden fry. (Here, we do take a diversion with our favorite “Cold-Fry” Frites, in which the potatoes and oil begin together at room temperature in a heavy-duty pot on top of a burner, with no need for a thermometer or a deep-fat fryer.)
Tips
• I swear by my mini electric fryer. It’s clean and simple, and with its built-in thermometer I don’t have to worry about moderating the temperature of the oil. The next best thing is a heavy-duty pot made from a good-quality material that heats up at a moderate speed and distributes and maintains heat evenly, such as stainless steel or cast iron.
• Getting the right oil temperature is essential. Too low a temperature means that a crust won’t form immediately on the food or not enough steam will be ejected from the interior of the food, both of which result in overabsorption of oil. Too high a temperature causes the outside to cook too fast, while the inside remains undercooked. Deep-frying is best done at 340° to 375°F (170° to 190°C), depending upon the batter used and the food that you are frying. In my tests, the hotter end of that spectrum gives me the best results and I always fry at 375°C (190°C). If you do not have a deep-fry or candy thermometer, a wooden chopstick dipped into the hot oil will vigorously fizz with little air bubbles at around 350°F (180°C).
• A neutral vegetable oil, such as sunflower oil, is best for deep-frying, as it won’t impart any flavor to the final product. An exception can be made for tempura; you might want to add a bit of sesame oil to your base oil for additional flavor.
• Food should be at room temperature and dry (unless it has a marinade on it) before frying.
• Food items should be cut to similar sizes so that ingredients cook at the same rate.
• Do not crowd the pot when frying, as it will lower the temperature of the oil too quickly. A good rule is never to cover more than one-third of the surface of the oil. Cook in batches, if necessary, either serving immediately or holding the finished items in a warm oven.
• Adjust the heat during cooking if the temperature drops too low, and bring it back up to temperature between batches.
• Always drain on paper towels after frying to absorb any oil.
• Season immediately after frying so that the seasoning adheres quickly to the crust.