The mixing potential of bubble column reactors for viscous fluids was investigated experimentally. A heterogeneously aerated pseudo-2D column was used to study hydrodynamics and especially low-frequency oscillation. Different metrological methods, such as particle image velocity, shadowgraphy, and pressure and oxygen sensors, were applied. Water and fluids with lower surface tension and higher viscosity but still showing Newtonian rheological behavior were used. A viscosity range of 1-100mPas was chosen to mimic bioreactor fluids. Two different spargers were employed to produce different bubble sizes and shapes. Injection flow rate was modified to create a wide spectrum of injection conditions. Different oscillating behaviors were found depending on the sparger and the fluid properties.