Definition: Hollow (of the bottle)

This term refers to the volume of air between the base of the cork and the level of liquid in the bottle. This volume, sometimes called the headspace, tends to increase when bottles are stored in conditions of insufficient humidity and excessive temperature. When the headspace becomes significant, the bottle is said to be low. The effect of wine oxidation is proportional to the volume of air. Be careful with bottles whose level is close to the shoulder of the bottle.