Abstract: An ice machine, tray, and tray insert are provided. A heat exchanger cools the liquid to freezing, then overcomes the heat of fusion to form ice. The tray includes an energy transfer surface in thermal contact with the heat exchanger to define a liquid/ice boundary layer. The tray further includes at least one freezing cavity. An egress area is defined in the tray above the freezing cavity. An insert traps a small volume of liquid, thus hindering movement of the liquid underneath the inserts and providing a nucleation/seed site. A mixing mechanism displaces the liquid thereby causing the liquid to flow to create a velocity profile at the liquid/ice boundary layer to create a directional freezing process starting from the energy transfer surface of the tray in thermal contact with the heat exchanger and growing through the freezing cavity up to the egress area.