An aqueous heating medium was prepared using only NaCl, and without adding any citric acid or sodium bicarbonate. The initial pH of the heating medium happened to be 5.52 at the same initial electrical conductivity. Ohmic heating was performed as previously described, such that the time–temperature and time–current histories were as same as those of the metallic electrodes. Analysis of electrode corrosion, and measurements of hydrogen generation and pH were also carried out as described above. Identification of the chemical nature of some elemental carbon species migrating into the heating medium was attempted by using gas chromatography–mass spectrometry (GC–MS), and electrospray ionization–mass spectrometry (ESI–MS), as described below.