The Shun Lee Cookbook - Michael Tong [11]
The temperature of the oil is the key to passing through. The oil should be hot enough to cook the food but not hot enough to brown it: 300° to 325°F. (Higher temperatures are reserved for true deep-frying, where the food will develop a crisp golden brown crust.) With the wok preheated, the oil will take only a few minutes to reach the proper temperature. Do not underestimate the value of a deep-frying thermometer. If you don’t have one, you can gauge the temperature of the oil with a ½-inch cube of white bread: it should take at least a minute to brown in the hot oil. But unless you are an experienced cook, use the thermometer.
The protein food (meat, poultry, or seafood) will have been marinated in the egg-white/starch coating. Carefully add the food to the hot oil, one or two pieces at a time, taking care that you don’t splash the oil. Add the food quickly, but do not dump everything in at once, and try to keep the pieces as separate as possible so they don’t stick together. The food will sink to the bottom of the wok, where the oil around it will bubble, but not furiously. The temperature will drop when the cool food is added, so keep the heat on very high to help the oil return to its original temperature. When all of the food has been added, stir the food gently or quickly, depending on the recipe, with the metal scoop to keep the pieces from clinging to each other. Cook until the pieces of chicken, shrimp, or fish turn white on the surface, about 45 seconds; or until pieces of beef or pork turn a light brown (which could take a bit longer, depending on the size of the pieces). Use the strainer to transfer the food to the colander.
In most cases, you will now (carefully!) pour the hot oil into the metal can or bowl, leaving 2 tablespoons of the oil in the wok. Let the oil stand to cool completely in the can before discarding it. If you have a subsequent frying step, be sure to heat the oil in the wok to the required temperature before continuing.
Stir-Frying
Stir-frying—in fact, all cooking in a wok—developed from cooking over a direct flame. Therefore, the Chinese became used to cooking with very high heat (not to discount the slow-cooking methods of braising and poaching). One advantage to high heat is that it sears in moisture and flavor and helps retain crisp textures. While the high flame on a gas stove is preferable, you can get excellent results from a flat-bottomed wok on an electric stove.
After the food has been passed through, all but a couple of tablespoons of the oil are discarded from the wok. The ingredients for the sauce base should be stirred together in a small bowl; if the sauce includes sugar, stir until the sugar has dissolved. In another small bowl, dissolve the thickening agent (almost always cornstarch) in water: Sprinkle the cornstarch over the water and it will dissolve smoothly. If you put cornstarch in the bowl and add water, it will lump. Before adding the sauce and thickener to the wok, stir them to blend in any ingredients that may have settled in the bottom of the bowl.
With the sauce and thickening liquid ready, and the remaining ingredients prepared, you are ready to do the actual stir-frying. Each step will happen very quickly, requiring only about 20 seconds, so you are only a minute or so away from eating.
Return the wok to high heat and heat the oil until it is shimmering, which is the indication that it can’t get any hotter without smoking. (Avoid heating oil until it smokes, as that is an indication that the oil is breaking down and the flavor will be altered.) From here, each recipe varies in how the ingredients are added, but in any case, hold the wok with one hand and use the other to stir the ingredients vigorously with the metal wok scoop. The idea is to keep the food in constant motion, so if you are feeling especially athletic, you can shake the wok with one hand while