Many people steam rice by putting the rice in the water and then bringing it to a boil. However, if you reverse the order—boiling the water first and then adding the rice—you can better preserve the vitamin B1 in the rice.
Vitamin B1 is a major nutrient in rice that protects the nervous system and promotes gastrointestinal motility and increases appetite. Its deficiency can lead to polyneuritis, beriberi, and even symptoms such as numbness in the limbs, muscle atrophy, lower limb edema, and heart failure. Therefore, in your daily diet, you should try to avoid the loss of vitamin B1.
The tap water we normally use is disinfected with chlorine. If you cook rice directly with this water, the chlorine in the water will significantly destroy the vitamin B1 in the rice, causing nutritional loss.
If you boil the water first and then add the rice, the chlorine in the water will have mostly evaporated, which will reduce the destruction of vitamin B1. For those who use electric cookers and pressure cookers, it is inconvenient to separate the water and rice, so you can use boiling water to cook rice. Rice contains a large amount of starch; these starch granules are insoluble in cold water. Cooking rice with boiling water allows the rice to be in hot water at a higher temperature from the beginning, which is beneficial for the swelling and rupture of the starch, allowing it to turn into a paste more quickly and making it easier for the human body to digest and absorb.