The wok is used for many forms of cooking, but its primary use is for stir-frying. It is uniquely suited for this technique, in which food cut into manageable pieces is cooked over high heat in a little fat or oil while being tossed about with a wide spatula. Because the food cooks quickly, you should organize the ingredients before you begin.
Turn the heat up under the wok to its highest level. When the wok is very hot, the bottom few inches begin to shimmer with subtle rainbow colors, somewhat like the reflection of light from oil. The Chinese call this “turning red”. Depending on how hot the flame is, it can take anywhere from 20 seconds to more than a minute to reach this stage.
When the wok is hot enough, add the oil. For most dishes, 2 to 3 tablespoons is sufficient. Pour the oil so that the stream hits the side of the wok about halfway up and dribbles down the side to the center. Move the stream around the wok as you pour.
The oil heats in a few seconds. When the surface ripples slightly, it is hot enough to add seasonings to flavor the oil—sliced ginger root, crushed garlic, dried chili peppers, or, in some dishes, salt. Press ginger or garlic with the spatula to release the flavors. The pieces of ginger and garlic can be removed or left in, to your own taste. Work quickly, so that the pieces of ginger or garlic do not burn and become bitter.
Add the main ingredient to brown and begin to cook in the flavored oil. Meat and poultry must be left untouched for a few seconds to begin browning properly.
Vegetables must be kept moving from the moment they hit the wok. It is not necessary to work rapidly, but do work smoothly.
Remember, the main heat source is at the center, so keep tossing the vegetables from the center of the wok up onto the sides so that they don’t burn. If the heat source seems too hot, lower it and add a couple of tablespoons of water or stock to cool the oil down a bit. This is a matter of judgment that comes with experience; follow your intuition.