1, first of all, first use cold water to wash the green beans into the pot, and then add hot water. In the process of cooking, if the water is not enough, do not add cold water, continue to heat the water, so that if you cook the soup is also green.

2, secondly, high heat cooking beans should pay attention to the beans to cook through, that is, green beans cooked to flowering, so eat not only delicious, but also do not have to worry about the soup color will become red, nutritional value is also more high. Part of the porridge, like to put some edible alkali, so it is easy to trigger a reaction, the soup will turn red. Although this will make the beans quickly cooked, but it is not recommended to do so, because the beans in the nutrients will be lost.

3, moreover, the best way to cover the pot when boiling soup. Because of the fear of overcooking, many people in the process of cooking, in order to always observe its form, it will directly open the lid of the pot. Mung bean skin polyphenols, in contact with oxygen, if oxidized into quinones, soup color will deepen. Usually when you cook can open a small fire, the lid on the pot, so you can better avoid oxidation reaction.

4, finally, the water boiled before putting green beans. Most families do green bean soup, will be green beans and water together in the pot, the correct way is to boil the water first, and then switch to a small fire into the green beans, this way to cook out of the soup color is the best. At this time, the dissolved substances are the active ingredients in the bean skin, not only the strongest ability to clear heat, but also not easy to oxidize.