It has been found, in this study, that a new ethanol-type fermentation can be obtained in a continuous flow, high-rate acidogenic reactor receiving molasses as the feed. The operating pH must be maintained at about 4.5 to avoid onset of propionic fermentation. The acidogenic reactor had a VSS level of 20g/L and its organic loading was as high as 80 to 90kg COD/m3d. The operating ORP was around −250mV. The ethanol-type fermentation was characterized by a simultaneous production of acetic acid and ethanol, while the yield of propionic was minimal even at a high organic loading rate of 80 to 90kg COD/m3d, and also, the hydrogen partial pressure was as high as 50kPa. Thus, this study has shown that the production of propionic acid is not always related to high hydrogen partial pressure. When the operating pH was increased to 5.5, the yield of propionic acid became significant.