Blanching, defined as a quick application of intense heat to foods, can be done with water or, less commonly, oil. The most common example of oil blanching is the pretreatment of meat by restaurant chefs before stir-frying: the chef quickly blanches the meat in oil, drains it, and then adds it to the stir-fry. The technique is controversial, however, because it's calorie- and labor-intensive and largely unnecessary.
Oil blanching tenderizes, brings out a food's flavor, adds richness and introduces some of flavor of the oil to the dish. Oil blanching also pulls some of the food's flavor back out into the oil, so this process is sometimes used to create herb and other flavored oils.
As a technique, oil blanching can be applied to vegetables, meats and fish. When used to pretreat vegetables, oil blanching destroys surface enzymes, loosens skin and melts any waxy layer that might have been applied by the market. When applied to meat or fish, oil blanching tenderizes the tissues and delivers a fattier mouthfeel. However, oil blanching adds lots of calories, uses a large amount of fat and adds labor-intensive steps to the cooking process.
Oil blanching has different effects, depending on the cooking temperature at which the blanching oil is introduced to the food. When the temperature is below 200 degrees Fahrenheit and the blanching oil contacts the food, the effect is that of a wet process, such as boiling or steaming. At these lower temperatures, the oil soaks into the food and remains there while the rest of the cooking takes place. When the temperature is above 325 F, the process is more of a dry one, such as searing or grilling. At these temperatures, water inside the food becomes steam, and the evaporating fluid prevents much of the oil from sinking into the food.
As a pretreatment technique, oil blanching is fairly straightforward. First, thoroughly dry the food you will be cooking. This allows the oil to cover the food's surface entirely and delivers a more evenly blanched product. Then, using a metal strainer, gently dip the food into a vat of hot oil, making sure that the food is completely under the surface and that you don't risk a burn by splashing the oil onto your skin. After just a few seconds, remove the food steadily from the oil and carefully shake off excess oil. Set the oil-blanched food on a plate covered with paper towels to soak up further excess. At this point, you're ready to proceed with cooking your recipe. If your recipe calls for oil blanching but you want less fat in the dish, you can omit the technique entirely.
- Photo Credit Eising/Digital Vision/Getty Images