If it tastes a bit sour, the most likely reason is that the temperature of the place where the glutinous rice is placed is too high. I often encounter this situation. It is not a matter of too much water or too little water, too much water. I just said that the sweetness of the sweet wine is very light but not sour. If there is too much water, the sweet wine will gradually become sweeter if it is left for two days at most. However, once there is a sour taste, the sweet wine should have gone bad. The temperature of making sweet wine is very important.