An aerosol generating device for heating an aerosol-forming substrate. The device comprises a storage portion 101 for storing the aerosol-forming substrate and a vaporizer 105 for heating the aerosol-forming substrate to form an aerosol. The storage portion 101 has an outer housing and an internal passageway 103, the storage portion forming a reservoir for the aerosol-forming substrate between the outer housing and the internal passageway, and the vaporizer 105 extends at least partially inside the internal passageway 103 in the storage portion101. The device further comprises a porous interface 107 at least partially lining the internal passageway 103 for conveying the aerosol-forming substrate from the storage portion 101 towards the vaporizer 105
