The in situ study of the linear viscoelastic behaviour of complex biological materials with changing volume, such as fermenting dough, poses great challenges to the rheologist. The aim of this study is to develop a new methodology involving a parallel-plate setup with an adjustable gap, to enable time-tracking of the dynamic moduli and density of fermenting dough. Frequency sweep snapshots at specific points in time were obtained in multiwave mode to reduce measurement times, and overfilling effects were taken into account by establishing a calibration curve with unfermented dough. The new test protocol allowed to distinguish the rheological impact of the CO2 gas from that of the other metabolites produced during fermentation. A further validation of the test protocol was achieved by studying the impact of sugar and salt on the fermentation kinetics, for which the results of the oscillatory tests were combined with gas production data obtained with a rheofermentometer.