Effect of Spent Wash Recycling on Fermentation of Corn Mashes

Distilled spent wash obtained after the distillation of fermented corn mash was reused in various proportions, in the subsequent fermentations to replace the process water and to reduce the effluent treatment cost. Successive recyclings of dealcoholised laboratory wash were carried out at 50% as well as 100% level and the parameters were monitored over three successive mashings and fermentations. Although the recyclings caused gradual buildup of residual solids over successive fermentations but had no deteriorating effect. The replacements, however, proved to be beneficial in the processes and improved the mashing as well as fermentation efficiencies where the alcohol yield went up by 375 ml kg -1 of the corn. The recyclings also reduced the attenuation time and exerted an increased buffering action during the fermentations.