Why is there a space left at the bottleneck of wine?
The space from cork to wine surface in the bottle, where wine doesn’t exist, is left for air. Generally, N is called “ullage”, which is decided by the capacity of the bottle and the measured volume of wine. According to the measurement requirements specified by the state, the measured volume of wine is unchanged. As for the package above 500ML, there is only 2% minus deviation when the average capacity is guaranteed to reach the packaging requirements. Therefore, ullage in the bottle is definite basically. The existence of ullage, firstly, is available for balancing the volume change of wine caused by environmental change during the storage period, and secondly, it can guarantee the existence of a slight amount of air in the bottle, which makes wine contact with a slight amount of air and facilitates the maturity of wine. Ullage is an important index for wine collectors or fans. The less the ullage is, the less the air is and the longer wine can be stored. With regard to wine in the storage period, ullage is related to environmental temperature and age. The lower the temperature is, the more the ullage is; the longer the age is, the more the ullage is.