Abstract The effect of ethylenediaminetetraacetic acid (EDTA), potassium ferrocyanide, and sodium potassium tartarate on ethanol production from cane molasses by Saccharomyces cerevisiae was investigated on simulated batch pilot-plant scale conditions for ethanolic fermentation of molasses. Ethanol production was very sensitive to EDTA as compared to potassium ferrocyanide and sodium potassium tartarate. When added at the time of inoculation, EDTA at a concentration of 50 mg l −1 produced maximum stimulatory effect on ethanol production, which was 30% more than in the control cultures. Sodium potassium tartarate and potassium ferrocyanide also produced stimulatory effects but at much higher concentrations than EDTA. Potassium ferrocyanide showed an inhibitory effect after initial stimulation, as did sodium potassium tartarate. Addition of these complexing agents during the propagation stage produced much less stimulation than addition during inoculation. Except for EDTA, which showed a gradual stimulatory effect up to a concentration of 1,000 mg l −1, other agents inhibited the earlier stimulatory effect. During the fermentation stage, addition of these complexing agents did not result in a marked change in ethanol production, and ethanol production values for EDTA, potassium ferrocyanide, and sodium potassium tartarate varied within very narrow limits. It was interesting to note that under the concentrations tested for the complexing agents, ethanol production values were never less than the control.