Abstract: An apparatus for manufacturing readily soluble granular substances from powdered materials such as, for example, coffee, milk and the like. The apparatus has a vertical outer hollow cylindrical body for allowing quantities of powdered material from a distributor to fall by gravity therethrough, and a vertical inner hollow cylindrical body of different length and diameter inside the outer cylindrical body. The two concentric cylindrical bodies partly overlap each other and define a circumferential gap therebetween extending along the overlapping portion. A pneumatic air supply is provided on the outer cylindrical body for introducing compressed air into the outer body and producing a whirling air stream in the gap so that the powdered material carried by the whirling air stream forms a thin, ring-like continuous curtain.