A method that includes clarifying a thin stillage product in a mechanical processor to produce a fine suspended solids stream and a clarified thin stillage is provided. The method further includes providing the thin stillage product and the clarified thin stillage, separately or in a combined stream, to one or more evaporators to produce one or more reduced suspended solids streams, each stream having a reduced amount of suspended solids and a lower viscosity as compared to process streams having a comparable total solids content but containing a higher amount of suspended solids. The method can further included further processing of one or more of the reduced suspended solids streams to produce a bio-oil product.