The invention relates to a system for refilling a flask with liquid. Said system includes: a first liquid-containing flask (S), a second flask (R) that is to be refilled with the liquid from the first flask (S), the second flask being in an upturned position and including a pump that is mounted on the flask and provided with an open-air ventilation opening openable or closeable according to the position of the pump, a filling interface that connects both flasks, the interface comprising a liquid channel arranged between the two flasks so as to transfer the pressurized liquid from the first flask (S) to the second upturned flask (R) through the open open-air ventilation opening of the pump of the second flask, and a gas channel for discharging the gas contained in the second upturned flask (R) out of the flask.