We present an experimental study using mixtures of aqueous superabsorbent polymers (SAP) where we systematically investigate the influence of the size of grains that make up the fluid structure on the effective rheology and its domain of validity. In water, these polymer powder grains swell up to 200 times and form gel grains whose size can be controlled by controlling the size of the initial powder. The rheology of this mixture (water and touching grains) combines viscous, elastic and plastic aspects and can be characterized using the free-fall of spheres of different diameters (between 3 and 25 mmdiameter) and densities (from 2200 to 15000 kg/m 3). As the typical size of the gel grains was varied between 1 and 8 mm, there is a range where it becomes comparable to the size of the falling spheres. We observe five different motion regimes. (1) A linear regime where the sphere has a rapid and linear fall and reaches a constant terminal velocity. (2) An irregular regime where the sphere's velocity varies around a constant value. (3) An intermittent regime where periods of no-motion and periods of irregular falls follow one another.