Addition of fine solids to the fermenting medium was known to accelerate the growth of yeast and the production of flavor components by yeast. The mechanism of this phenomenon was investigated.
Effects of the addition of solids were observed in static culture but neither in shaking culture nor in cloudy medium. These effects were varied by the species of solids. The growth of yeast in the medium, added with various solids, depended upon the concentration of dissolved CO₂ in the medium (DCO₂), and the hydrophobicity of added solids related to the growth of yeast in the medium.
It was considered that the mechanism of the phenomenon was as follows ; The supersaturated DCO₂ in static culture, which is inhibitory to the growth of yeast, was decreased to theoretically saturated DCO₂ by the addition of hydrophobic solids, and then the inhibition of the growth of yeast was released.