Establishing consistent flow of biomass is important for determining biorefinery operations and viability, and a large contributor to shutdown of pioneer biorefineries. Toward characterizing biomass flow, INL implemented and developed state-of-the-art diagnostic tools for diverse biomass over a range of formats and processing methods. One common method for granular materials is shear testing to evaluate the internal friction and effective cohesion over a range of applied stress conditions. This yields a flow-function that describes material flow in different stresses/operations units and scale. Empirical design heuristics for granular materials based on these analyses do not translate to biomass, nevertheless, the tests offer qualitative comparisons between materials and processing techniques. These techniques include parallel plate viscometry, capillary rheology, and vane shear cell evaluation for wet and slurried feedstock; vane, Schulze ring, Peschl, and Linear shear cells; Johanson Indicizer; and a unique customized direct axial shear test fixture for dry (<30% moisture by mass) feedstock. These are complimented by classical load frame testing like bulk compressibility and elasticity . To evaluate larger scale flow performance of dry and wet materials, an adjustable, instruments wedge hopper, an instrumented feed bin and dosing auger system, and a wet material flow loop/segregation system are used.