For industrial applications, hydrogen production rates and yields need to be maximized, and at the same time, energy inputs need to be kept low. Optimizing reactor configuration is therefore an important consideration for developing a fermentative hydrogen production process. For practical dark fermentative hydrogen production, it is likely that large-scale reactors would be required, however it can be hard to adequately control all the operational parameters at this scale. Therefore, before proceeding to large-scale applications, it would be important to define the minimum requirements of the system at lab scale followed by application at pilot scale before proceeding to full scale-up.