A commercially available biomass monitor has been employed in a number of applications. For capacitance monitors, a relationship between capacitance measurement and cell counts or colony forming units has been reported in the literature. However, for use as an online instrument, a more practical correlation with the biomass concentration is needed. In this study, we followed the batch growth of brewer’s yeast and a correlation with viable biomass concentration (g DW/L) was demonstrated. This correlation was utilized with the capacitance biomass monitor in a control loop to maintain setpoint biomass levels in a cyclic reactor under perturbations. Not only did the system demonstrate the capability of the biomass monitor to control biomass in such a system, but it also confirmed the correlation reported in our earlier work.