The effect of water on the packing and flow properties of fine and coarse particles was experimentally investigated. Four different particle sizes of glass beads, from 5 to 275 m, were studied with increasing water weight-percentages. Using a FT4 Powder Rheometer, changes in bulk properties were collected as a function of water content and particle size. The results show that water content plays a significant role on the packing and flow of the particles. Small amounts of water created porous aggregates due to liquid bridging. Greater amounts of water resulted in the filling of the void-spaces. This was indicated by an increase in basic flow energy, density, and pressure drop, with a decrease in porosity. A greater understanding of bulk properties of wetted material is useful to develop standard systems that can be used to examine the behavior of more complex situations, and implement changes to improve materials handling and processing. (c) 2015 American Institute of Chemical Engineers AIChE J, 62: 648-658, 2016