Sometimes referred to as Isobaric Filling. By maintaining equal pressure between the tank and the container (bottle or can) in the filling process, leakage of carbon dioxide can be prevented. This is generally done by pressurising the container so that it matches the existing pressure of the liquid in the tank. When filling the container the liquid is poured in, simultaneously pushing out the CO2 of the container and the counter pressure that it creates keeps the foaming and leakage to a minimal.