Designation (also fill level) for the height of the liquid level in a wine bottle, barrels or other wine containers. The distance in the bottle between the lower end of the cork and the liquid level is ideally at least 10 to a maximum of 15 mm. Too much air (oxygen) causes undesirable oxidative processes and can accelerate the ageing of the wine. For this reason, modern bottling plants fill the gap with inert gas
Leaky or defective corks lead to a loss of liquid through evaporation and, depending on the state of damage, more or less penetration of oxygen from the outside. The greater this loss and thus the greater the amount of air, the greater the risk of oxidation. During prolonged bottle storage, if natural corks are used (not plastic corks or other types of closure), a small amount of wine is absorbed by the cork, which can result in a reduction of up to half a centimetre in the neck of the bottle. Certain producers, such as Château Mouton-Rothschild (since the 1991 vintage), therefore use shorter corks.