Apparatus, systems and methods for carbothermically producing aluminum are disclosed. The systems may include a reactor and an electrical supply. The reactor may include a plurality of side-entering electrodes and a top-entering electrode. The electrical supply may be operable to supply multiphase current to the side-entering electrodes and/or the top-entering electrodes. The electrodes may be in communication with a molten bath of the reactor, and the multiphase current supplied thereto may be passed through the bath to heat the reactor. The amount of current supplied to various electrode sets may be adjusted to facilitate tailored heating of the molten bath.