There is provided an aerosol generating device for heating an aerosol-forming substrate, including a storage portion for storing the aerosol-forming substrate and a vaporizer for heating the aerosol-forming substrate to form an aerosol. The storage portion has an outer housing and an internal passageway, the storage portion forming a reservoir for the aerosol-forming substrate between the outer housing and the internal passageway, and the vaporizer extends at least partially inside the internal passageway in the storage portion. The device further includes a porous interface at least partially lining the internal passageway for conveying the aerosol-forming substrate from the storage portion towards the vaporizer.