Optimization of Fermentation Parameters in a Brewery: Modulation of Yeast Growth and Yeast Cell Viability

The growth and viability of yeast cells used for fermentation of lager beer (anaerobic process) were optimized under high-gravity brewing conditions (15.5 °P) in an industrial plant. The influence of different levels of pitching rates (6–10 million cells/mL), aeration (8–12 mgO2/L), times (4.5–13.5 h) of filling cylindroconical tanks (CCTs) (3850 hL), and different fermentation temperatures (8.5–11.5 °C) on the multiplication of yeast biomass and the percentage of dead yeast cells was investigated using a response surface methodology (RSM, Box–Behnken design). The obtained results of the influence of the tested parameters on the increase in yeast biomass and their viability were characterized by statistical significance (p < 0.05). Except for the fermentation temperature, which had no effect on the viability of fermenting yeast cells, all independent variables affected both the yeast growth and yeast cell viability.