Fried beans need to blanch. Knife beans need to be blanched before frying, because the knife beans are relatively hard, itself has a special smell, after blanching can remove the odor, taste more tender. Knife beans selection method: pods long and like a tube, brittle and soft body, common white bean curd and green bean curd two kinds. In the purchase of bean curd, generally to bean strip thickness uniformity, bright color, transparent and shiny, full of seeds for the best, and there are cracks, skin wrinkles, strip too thin without children, skin with insect marks of the bean curd should not be purchased. Selection of young pods, to pod green, smooth skin hairless, large and wide thick is good. When mature, the pod skin becomes light yellow-brown, hard and inedible. When choosing dry seeds, look at the seeds should be free of insects, smooth skin, full, pink or light purple-red, flat oval, umbilical cord black-brown. Fresh dry seeds are easy to cook crisp, and sand and glutinous.