Production and Evaluation of Shochu produced from a 8, 300l Morimi-mash containing Post-distillation Slurry using a Newly Developed Recycling Process

Abstract

In order to commercialize a newly developed recycling process, shochu was made using a fermentor with a working volume of 8, 300l. 1, 500kg of rice was added twice, on the first and the third day, to 5, 300l of post-distillation slurry which had been discharged from the vacuum- distillation process used in the conventional method. No problem was experienced in the newly developed recycling process using a two step addition of cooked rice, although the fermentor volume was increased from 1, 800l to 8, 300l for commercial use. The concentration of ethanol produced in a 7-d fermented mash reached 17.0% v/v and the concentration of glucose was less than 0.4 gl^-1. The 9-d fermented mash was then subjected to vacuum distillation and the production yield of pure ethanol was 470.5ml (kg of added rice)^-1. This value was almost identical to the yield obtained in the 1, 800l-scale experiment reported in our previous paper and was higher than the average yield (450ml kg^-1) obtained with the conventional method. With respect to the quality of the shochu the acetaldehyde concentration and acidity were slightly higher than the value obtained using the conventional method. However, these values decreased during the storage period. The acetaldehyde concentration and acidity were reduced to 25% and 75%, respectively, after a 10-d storage. Also, this shochu obtained a better score in the sensory test than that produced by the conventional method.