By means of the bioliq® process at Karlsruhe Institute of Technology, flash‐pyrolyzed straw is converted into slurries made of pyrolysis condensates and char. These slurries can be gasified to produce syngas and, subsequently, synthetic fuels and chemicals. Investigations show that a stable slurry of the pyrolysis products is not miscible, as the condensates tend to split into organic and an aqueous phases. Thus, application of two different slurries is suggested: The organic condensates can be gasified directly, and the aqueous condensates can be mixed with 40 wt % ground straw char. This latter slurry is the focus of this work, which describes the mixing, settling, and stirring behavior. Grinding the porous and elongated char particles decelerates sedimentation and also decreases the viscosity. Thus, higher‐concentrated slurries can be mixed, which leads to higher stability.