A cryogenic system as well as a method of generating a pressurized, sub-cooled mixed-phase cryogen and a method of delivering such a cryogen to a cryoprobe are disclosed. In an embodiment, the cryogenic system includes a reservoir containing a liquid cryogen and a sub-cooling coil immersed in the liquid cryogen. The cryogen is supplied to the sub-cooling coil and is cooled under pressure to produce a pressurized mixed phase cryogen within the sub-cooling coil. This pressurized mixed phase cryogen is provided via supply line to a cryo-device for use.