A stopcock for allowing or stopping the flow of a liquid under pressure through a dispensing tube comprising an upstream portion separated from a downstream portion by the stopcock to which they are both connected, said stopcock comprising: (a) A housing portion comprising a chamber defined by a housing peripheral wall surrounding a longitudinal z-axis, said housing peripheral wall comprising an inner surface of revolution about said longitudinal z-axis, said housing peripheral wall comprising a housing inlet opening connectable to the upstream portion of the dispensing tube, (b) An outlet connector connectable to or forming the downstream portion of the dispensing tube and comprising an outlet opening; (c) A plug defined by a plug outer peripheral wall snugly fitting the inner surface of revolution of the housing peripheral wall, such that the plug can rotate within the chamber about said longitudinal z-axis, said plug comprising (d) a through-channel at least partially transverse to the longitudinal z-axis, extending from an upstream opening located on the plug outer peripheral wall, to a downstream opening, such that the plug can be rotated about the longitudinal z-axis from a flow position of the plug, at which the upstream opening is in fluid communication with the housing inlet opening, and the downstream opening is in fluid communication with the outlet opening of the outlet connector, to a sealed position of the plug at which neither the upstream opening nor the downstream opening is in fluid communication with the housing inlet opening, wherein, (e) the plug outer peripheral wall comprises a seal protrusion topped by a ridge and forming a closed loop defining a blank area of the plug outer peripheral wall, such that, in the sealed position, the housing inlet opening of the housing peripheral wall faces the blank area and is circumscribed within the seal protrusion, characterized in that, • the plug outer peripheral wall further comprises a flow protrusion topped by a ridge circumscribing the upstream opening such that, in the flow position, the inlet opening of the cylindrical chamber peripheral wall is circumscribed by the flow protrusion. (a) A housing portion comprising a chamber defined by a housing peripheral wall surrounding a longitudinal z-axis, said housing peripheral wall comprising an inner surface of revolution about said longitudinal z-axis, said housing peripheral wall comprising a housing inlet opening connectable to the upstream portion of the dispensing tube, (b) An outlet connector connectable to or forming the downstream portion of the dispensing tube and comprising an outlet opening; (c) A plug defined by a plug outer peripheral wall snugly fitting the inner surface of revolution of the housing peripheral wall, such that the plug can rotate within the chamber about said longitudinal z-axis, said plug comprising (d) a through-channel at least partially transverse to the longitudinal z-axis, extending from an upstream opening located on the plug outer peripheral wall, to a downstream opening, such that the plug can be rotated about the longitudinal z-axis from a flow position of the plug, at which the upstream opening is in fluid communication with the housing inlet opening, and the downstream opening is in fluid communication with the outlet opening of the outlet connector, to a sealed position of the plug at which neither the upstream opening nor the downstream opening is in fluid communication with the housing inlet opening, wherein, (e) the plug outer peripheral wall comprises a seal protrusion topped by a ridge and forming a closed loop defining a blank area of the plug outer peripheral wall, such that, in the sealed position, the housing inlet opening of the housing peripheral wall faces the blank area and is circumscribed within the seal protrusion, characterized in that, • the plug outer peripheral wall further comprises a flow protrusion topped by a ridge circumscribing the upstream opening such that, in the flow position, the inlet opening of the cylindrical chamber peripheral wall is circumscribed by the flow protrusion. • the plug outer peripheral wall further comprises a flow protrusion topped by a ridge circumscribing the upstream opening such that, in the flow position, the inlet opening of the cylindrical chamber peripheral wall is circumscribed by the flow protrusion.