The present invention is an apparatus and process for cooling and de-steaming hot calcined stucco used in the production of gypsum boards or bagged plaster. The apparatus is a fluid bed stucco cooler and comprises a cooler housing having a plenum having a stucco inlet and stucco outlet. The stucco cooler includes a rotating disk in the plenum. The rotating disk includes nozzle for spraying fluid, and is attached to a rotable shaft extending from the side of the cooler also includes a fluidization pad and agitator to help to mix the air and the stucco powder to insure fluidization, prevent channeling, and prevent the stucco powder from building up on the various components. The air also forces steam from the hot calcined stucco out through an air outlet located at the top of the stucco cooler, thereby de-steaming the stucco. The stucco flows through the plenum and passes over the cooling coils, thereby cooling the stucco as it reaches the stucco outlet.