Abstract: A method of packing a temperature sensitive product utilizes a temperature controlled product shipper that includes a phase change material bladder which can be filled with a preconditioned brined-slurry PCM at the point of packaging. The temperature sensitive product is contained within a product box or master case, which is in turn packed inside an insulated liner and an outer box. The PCM bladder fits between the master case and the insulated liner and is filled with the preconditioned flowable PCM at the point of packing just before closing the box for shipment.