Anionic surfactant concentrates in the form of solid free-flowing powders and/or granules which may also be present as compounds in admixture with other auxiliaries and/or useful materials suitable for use in detergents and/or cleaning products and which have apparent densities of at least about 150 g/l are produced by hot drying of the water-containing preparations with superheated steam as the drying gas. Preferred apparent densities are above about 200 g/l and are preferably at least about 350 g/l. In addition, the pourable and free-flowing material is preferably in the form of a substantially dust-free material through the presence of dust-binding auxiliaries and/or useful materials and/or by regulation of the residual water content. In one preferred embodiment, the anionic surfactant concentrate is in the form of porous carrier beads with an absorbent porous inner structure.