Abstract: A device for producing an elongate ingot of clear ice comprises a housing comprising at least one flume surface wall that defines at least one elongate trough; at least one fluid intake disposed to provide a flow of liquid into the at least one elongate trough; at least one drain disposed to drain liquid from at least one elongate trough; wherein the at least a portion of the at least one flume surface wall is in thermal communication with a cooling source; and wherein the at least one fluid intake and the at least one drain are adapted to provide a substantially constant flow of fluid to the at least one elongate trough during a freezing operation of the device. The cooling source can be an internal cooling cavity.