Abstract Mass transfer through a liquid membrane was studied in a macroscopic setup that allowed an estimate of the resistance to interface crossing. It was found that the interfacial transfer was associated with the phase behavior and physicochemical formulation of the surfactant‐oil‐water system. The resistance to interfacial mass transfer closely followed the variation of interfacial tension, i.e., it was minimal at the optimal formulation of the so‐called Winsor III phase behavior systems.