This research involves the influence of tank scale and, additionally, stirrer speed, the volumetric gas flow rate, the sucrose concentration in aqueous solution, and the yeast suspension concentration on the hydrodynamics of gas-liquid and gas-biophase-liquid systems. A stirred tank with internal diameters of T=0.288m, and T=0.634 m was filled with a liquid to the height H=T. For measurements, two high-speed stirrers were used: a Rushton turbine stirrer (RT) and A 315 stirrer. The study was carried out for gas-liquid and biophase-gas-liquid systems, where the biophase was a suspension of Saccharomyces cerevisiae yeast, the gas phase was air, and the liquid phase was an aqueous solution of sucrose. The gas hold-up and power consumption depend on the scale of the tank. The experimental results were mathematically described. Eqs. (14)-(18) do not have equivalents in the literature.