The present invention provides a method and system for customization of flow characteristics of a support using permanent and controlled evacuation of interstitial gas during the manufacturing process. The flow characteristics can be customized to provide a stiffer or less stiff support by a comparative degree. The flow characteristics can be permanently changed. The support includes a bladder filled with a fluidized particulate material. The medium of the fluidized particulate material includes interstitial spaces. A predetermined amount of gas can be removed to provide a support having a desired specific support characteristic.