I'm from the countryside myself, and then when my family makes rice cakes, they always wash the rice with water first, then control the water to dry it, and then it seems to be sour all the time.

Don't wait for it to turn sour. When the water is dry, you can take it to powder, and then take it to the sun. It will dry in about two days, and then it can be used to make rice cakes. You can make more than a catty of powder for your family, and you can make as much as you eat. The rest of the powder can be put away in a bucket, and you can do it if you want.