Onion alcohol production by repeated batch process using a flocculating yeast

Alcohol production from worthless onions by a repeated batch process using a flocculating yeast was investigated. The juice from the cultivar red onion R-3, which contained 67.3 g/l of total sugar, was smoothly fermented by a repeated batch operation using the flocculating yeast IR-2. The productivity, the final ethanol concentration and the ethanol yield were about 6.5 g/l/h, 30.6 g/l and 91.9%, respectively. The onion alcohol produced could be used as a favorable source of onion vinegar or alcoholic beverage.