Various techniques used in winemaking range from "controlled supply of oxygen" to the total opposite "prevention of oxygen influence". Oxygen absorption occurs when the surface of the must / wine comes into contact with air. These are especially all activities where mechanical movement takes place, such as pressing, fining, filtration, deacidification, overpumping and bottling. But also during barrel ageing, a low supply of oxygen takes place through the vessel cavities in the wood, as well as during bottle ageing through oxygen permeable closures. The latter is also consciously controlled. Absorption is favoured by large liquid surfaces, such as those found in tanks or barrels or in turbulent flow conditions. Absorption is also enhanced by low temperatures.