Machinery like pumps used for the commercial production of yogurt and related fermented milks generate vibrations that can spread to the fermentation tanks. Such vibrations can disturb the gelation by causing texture defects including lumpiness and syneresis. The aim of this study was to research the effect of vibrations on the aggregating milk proteins and evaluate their relevance with regards to the manufacture of fermented milk products. To generate defined vibrational states, an experimental setup was developed consisting of a jacketed stainless steel tank (cylindric, d = 100 mm, l = 600 mm). Vibrations are directly introduced by a piston at the bottom, which is oscillated by an electrodynamic vibration exciter. Pressure sensors are used to describe the propagation of specific vibrations within the liquid. At a frequency of 30 Hz, a linear decrease of the pressure was observed. In contrast, a standing wave was formed at 1000 Hz. Vibrations (f = 30 Hz) were then applied during yogurt fermentation at 43°C by varying the amplitude from 0 – 10 m/s². After acidification, set milk gels were processed and analyzed (rheology, water-holding capacity). A method based on image analysis was applied to quantify visible particles and evaluate textures. The number of independent repetitions of the experiments was i ≥ 3. Vibrations of lower amplitudes (a = 2.5 m/s²) increased the number of visible particles by a factor of 2 (P < 0.05). Higher amplitudes (a ≥ 5 m/s²) resulted in considerable syneresis of the set gel and a less homogeneous appearance of the final product. The particle number was increased by a factor of 10 to 20 (P < 0.001), however, deeper analysis revealed that particle formation was more pronounced in the lower and upper area within the fermenter. A high particle number was also linked to a reduced product viscosity and increased whey separation. In conclusion, the magnitude of a specific vibration depends on both its characteristics and other process parameters. Manufacturers of fermented milk products should consider vibrations as a further cause for quality defects.