The present invention provides a valve arrangement for location on a vessel for holding liquids, comprising: a supporting member configured to form a valve seat; a deformable sealing member located against said valve seat and arranged for deformation under an applied pressure to present a first gap between said sealing member and said valve seat in a region where pressure is applied to allow a liquid to be dispensed from the vessel via said valve arrangement, and a second gap between said sealing member and a valve seat in a region where pressure is applied, to allow air to enter said valve arrangement.