To proceed mass production and improve its quality, we fermented potatoes using pilot system and investigated the changes in components during fermentation. After liquefaction and saccharification of potatoes by Nuruk(group I), crude enzyme(group II) and glucoamylase(group III), sugar contents in all groups were 18brix equally. However sugar contents in group(II) and group(III) after 24hrs decreased deeply to 7.2 and 8.8 % respectively, after 24hrs. Alcohol content in group(I) increased slowly and was the highest such as 6.8% after 48hrs. Fusel oils in all groups were n-propanol, isobutanol and isoamylalcohol. The major fusel oil in all groups was isoamylalcohol. At the early stage of fermentation, free sugars were glucose, maltose and lactose. Glucose decreased deeply during fermentation and at latter of the fermentation, galactose was detected in all groups. The contents of total free amino acid were 516.57~569.98 mg% in group(I), 193.97~292.11 mg% in group (II) and 186.31~270.53 mg% in group(III). The contents of aspartic acid, serine, glutamic acid, alanine, arginine, and histidine were high in all groups.