PURPOSE: To obtain an edible vinegar sanitarily in high yield in a short time in preparing the edible vinegar in a closed fermentation tank by the stationary fermentation method, by adjusting the oxygen concentration in the fermentation tank to keep the concentration always within a given range.
CONSTITUTION: A raw material unrefined SAKE 2 is introduced into a closed fermentation tank 1 and inoculated with acetic acid bacteria to prepare an edible vinegar by the stationary fermentation method. In the process, at least two positions of the vapor phase part 3 formed in the top of the tank 1 are communicated with a recirculating pipe 4 having a temperature controlling apparatus 5 and a gas circulating apparatus 6, and an oxygen concentration sensor element 11 is inserted in the vapor phase circulating path 4 to measure the oxygen concentration in the vapor phase part 3. If the oxygen concentration is reduced below the specified value during the fermentation, an air supplying apparatus 10 is automatically operated to keep the oxygen concentration in the vapor phase part 3 at 5W19 (V/V)%. The temperature of the vapor phase part 3 is controlled by the temperature controlling apparatus 5 to keep the surface layer of the unrefined SAKE 2 within about 30±2°C range.
ODAKA YASUYOSHI
WATANABE ISAMU
INOUE MASARU
