The kinetics of the infiltration of liquids into powder agglomerates has been studied relative to its influence on changes in buoyancy of the agglomerate. A model relating the instantaneous buoyancy to the degree of fluid penetration into a spherical agglomerate is presented. Experiments in which poly(dimethylsiloxane) fluids infiltrated various agglomerates of silica, titanium dioxide, and carbon black confirmed the validity of the model and the method as a means to assess the degree of infiltration.