The key to brewing is to master the fermentation time. Soak the good corn in water for half a day, then steam it in a cage, spread it out to dry and loosen it. After cooling, add a certain proportion of distiller's yeast and stir evenly. Put the corn into a wide-mouth container, smooth the corn rice, and leave a round hole in the middle. Then sealing, preserving heat and fermenting. Two days at most in summer, and 3-4 days at room temperature 18 degrees in winter. The fermentation process should not be too long. For too long, the starch in the corn is converted into alcohol, and the wine is not sweet. Because of the high alcohol content, people say it is too strong. The technical point of the whole process is that all containers should be clean and oil-free; The proportion of koji is appropriate and the fermentation time is just right. The wine fermented at this time is sweet and mellow.