Many people steam rice by putting the rice in cold 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, it helps protect the nervous system and promotes gastrointestinal motility and increases appetite. In daily diet, the loss of vitamin B1 should be avoided as much as possible.
The tap water we usually use for cooking is disinfected with chlorine. If you use this water directly to cook rice, the chlorine in the water will destroy a large amount of vitamin B1 in the rice. If you boil the water first and then add the rice, the chlorine in the water has basically evaporated, which will reduce the damage to vitamin B1.
When using a rice cooker or a pressure cooker to make rice, it is inconvenient to separate the water and the rice, so you can use boiled water to cook the rice. Rice contains a large amount of starch, and these starch granules are not soluble 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 to the swelling and rupture of the starch, making it turn into a paste state more quickly and easier for the human body to digest and absorb.