The drying process of peony is divided into four stages:
In the first stage, the temperature is controlled at 45°C, the humidity is 30%, and it should be baked for 2 hours.
The temperature of the second stage is controlled at 50°C, the humidity is 20%, and it should be baked for 6 hours.
The temperature of the third stage is controlled at 58℃, the humidity is 15%, and the drying time is 12 hours.
In the fourth stage, the temperature is controlled at 68°C, the humidity is 10%, and the drying process is performed for 4 hours.