If it turns sour, it's nothing more than that you didn't wash the steamed rice clean, or the distilled water in the steamed rice is congenital, and various vegetable soups have been dropped in it. Because the weather is hot and the temperature is high, the distilled water left before has turned sour for a long time, but you haven't changed it, so the steamed corn sparerib soup will definitely be a little sour.