There is provided an electrically heated smoking system comprising a shell (101) and a replaceable mouthpiece (201). The shell (101) comprises an electric power supply (103) and electric circuitry (105). The mouthpiece (201) comprises a liquid storage portion (203) and a capillary wick (207) having a first end (207a) and a second end (207b). The first end (207a) of the wick extends into the liquid storage portion for contact with liquid (205) therein. The mouthpiece also comprises a heating element (209) for heating the second end (207b) of the capillary wick, an air outlet (211), and an aerosol forming chamber (213) between the second end (207b) of the capillary wick and the air outlet (211). When the shell (101) and mouthpiece (201) are engaged, the heating element (209) is in electrical connection with the power supply (103) via the circuitry (105), and a flow route for air is defined from at least one air inlet (115) to the air outlet (211) via the aerosol forming chamber (213). In use, liquid (205) is transferred from the liquid storage portion (203) towards the heating element (209) by capillary action in the wick (207). Liquid at the second end of the capillary wick is vaporised by the heating element (209). The supersaturated vapour created, is mixed and carried in the air flow from the at least one air inlet (115) to the aerosol forming chamber (213). In the aerosol forming chamber (213), the vapour condenses to form an aerosol, which is carried towards the air outlet (211) into the mouth of a user.