i think that you need to get even heat under the base - i think it made a different to the taste of my morning coffee (s) when i suspended it above heat (using wire) to get even heat under the device. and don't clean your device with too much using dishwashing liquid - try to use only water most of the time.
re: additional points on stove top method
i think that you need to get even heat under the base - i think it made a different to the taste of my morning coffee (s) when i suspended it above heat (using wire) to get even heat under the device. and don't clean your device with too much using dishwashing liquid - try to use only water most of the time.