The present set of embodiments relate to a bioproduction system, method, and apparatus for mixing a fluid. The bioproduction mixing system includes an offset helical assembly having a stabilizer and impeller for mixing a fluid within a flexible compartment The bioproduction mixing system is designed for efficient mixing of the fluid and for use with a variety of different impellers that can be located at different locations according to the volume and shape characteristics of the flexible compartment. The bioproduction mixing system is optimized to eliminate stagnation zones while maximizing bulk fluid flow.