Blanching string beans takes about six minutes to cook.

If you add a little salt or vinegar to the water, the beans will turn bright green. If you can't grasp this degree, you can feel almost, take a bean curd bite, no bean flavor and mouth dry crisp, it means you can, you should immediately put out in cold water to cool down.

The bean curd is an annual vegetable of the genus cowpea of the family Leguminosae of the order Rosaceae. It is also known as cowpea, long cowpea and banded bean. Rich in protein, carotene, high nutritional value and good taste, it is one of the popular vegetables widely cultivated in the north of China, and its popularity ranks first among all kinds of vegetables.

Beans are highly adaptable, can be cultivated in the open ground, can also be protected planting, but also can be produced annually, four seasons on the market.