Fermentation - Various types of continuous fermentation plants are available for producing ethanol, where sometimes several fermenters are connected in a series. In a typical fermenter using molasses as a substrate, diammonium phosphate (as a source of nitrogen. for the yeast) is mixed up with the substrate.

The pH is maintained at 5. 0 and fermentation is carried out at 30-35°C. After fermentation, yeast cells are separated by centrifugation or sedimentation and used again.