A defibering and deflaking pulper has a defibering rotor-stator pair and a deflaking rotor-stator pair for processing a fiber-based material into smaller pieces. The defibering and deflaking pulper creates an impeller-produced vortical circulation that pulls the material through a defibering rotor-stator interface, where the material is broken down into smaller pieces, and then through a deflaking rotor-stator interface, where the smaller pieces are broken down into even smaller pieces. The defibering and deflaking pulper accumulates the defibered and deflaked material that passes through the defibering rotor-stator interface and the deflaking rotor-stator interface for further processing. This combination of defibering and deflaking in the defibering and deflaking pulper reduces plugging from larger pieces of the material and reduces downstream processing of the material, thus increasing productivity and reducing costs.