Rice is often thought to be the basic staple in China, but this is true only south of the Yang-tze River. Wheat is the primary source of starch in the north because the soil and dry, cold climate are more suited to wheat cultivation. Some dry-field rice is planted north of the Yangtze, but production is limited. Even though simple economics long made it impractical to ship grains from one part of China to another, the distinction between rice and wheat diets has never been complete. Northern Chinese occasionally ate rice, and a number of wheaten foods were incorporated into southern cooking styles. But even with the improvement in transportation facilities, northerners have continued to prefer wheat over rice.
Wheaten foods can be divided into three general categories, depending upon how the dough is made. Leavened dough is used for a variety of steamed and baked breads.
Unleavened dough prepared with cold water gives a more chewy consistency to the final product, and is preferred for noodles and boiled dumplings. And dough made with hot water partially cooks the flour, making the final consistency softer; this prevents steamed dumplings and other wheaten foods fried in oil, such as pot stickers, from drying out and becoming hard or rubbery.