Abstract The microstructures of six sawdust packings, three fresh and three dried, are studied by using three-dimensional X-ray microtomography data. Packings are highly disordered and are considered as porous media resulting from a stochastic process. To describe the packings, three categories of properties are defined and exploited. They are all based on the phase indicator function. The first set gives information about the geometry of the packings. The second set covers morphological parameters linked with the particles and the pores of the packings. The third set describes the connectedness of the porosity, i.e. the topology of the packings. Fresh and dried sawdust packings are compared based on the three sets of properties. The packing topology is the same for dry and wet sawdust. Dry packings have a slightly larger porosity than wet packings, by about 4%. The pore diameters are also larger in dry packings, by about a factor 2. But the specific surfaces are smaller for dry packings, by about 30%. Finally, while the sawdust particles are anisotropic, all categories of parameters show that beds are isotropic.