A condenser was designed and developed for distillation of herbaceous oils. The performance of the condenser was evaluated by using two common refrigerants namely R12 and R134a to separate the water and essential oil molecules of spearmint (Mentha spicata) leaves from a vapor-air mixture flow. Three levels of air speed (1, 2 and 3 m/s) and temperature (180, 210 and 250 °C) were selected for the vapor-air mixture flow during the experiments. For this condenser, a better performance was observed for the R12 than the R134a refrigerant. The best performance of the condenser was obtained at lower air speeds and lower temperatures for the essential oil of spearmint leaves.