In situ rheological monitoring of a semi-batch emulsification process for the production of a simplified cosmetic lotion formulation has been realized in a rheo-reactor (100 mL volume), which consists of a small-scale reactor connected to a rheometer. The torque evolution as well as the mechanical spectrum evolution has been reported for two different protocols. It has been shown that the evolution of the rheological properties of the macroemulsion seems to be governed by the gelification of the continuous aqueous phase. In situ rheological characterizations of the macroemulsion at the end of the process, under controlled mechanical history mimicking somehow post-processing "real life" of the cosmetic lotion, have shown that the stability can be significantly influenced by the process protocol.