Soy sauce is atomized into 10-200μm drops during the spray drying process, and the surface area will be larger when atomized into drops, the heat exchanges quickly between the drops and air, and the drops become powder in a few seconds and come out of the drying room soon.
Though the temperature of soy sauce drops is 100 centigrade, but the temperature of soy sauce powder is just 45-55 centigrade. The whole drying process only causes a little damage to the quality. Soy sauce powder can be made by pressure spray drying process and also centrifugal spray drying process. Soy sauce powder made by centrifugal spray drying process has large granules and is free flowing, but not with long shelf life because there are many little bubbles in it. If the centigrade is too high, the soy sauce powder will be over heated which leads high impurities concentration and bitter taste in it.
To get high quality soy sauce powder, manufacturers would like to use pressure spray drying process. In general, the pressure is 16-20MPa, the temperature of the incoming wind is 140-150 centigrade, the temperature in room is about 120 centigrade, the output wind is 115-125 centigrade. According to the demands of the quality (color, moisture, flavor, etc), the parameters above are adjustable.