Kagoshima no Tsubozukuri Kurozu

　From the Edo period (1600 - 1868), vinegar made from rice as a raw material in Fukuyama Town, Kagoshima Prefecture, is brewed using an outdoor pot. As this vinegar goes through the aging process, it takes on the color of amber, so it is called Kagoshima no Tsubozukuri Kurozu (Kagoshima's black pot vinegar, hereafter, black vinegar).

　Its production method is unique in that fermentation is carried out by using outdoor jars, and after aging, its color changes from brown to black-brown. A characteristic aroma and mellow sourness are said to be developed in the course of this long-term aging. Compared to ordinary rice vinegar, black vinegar contains abundant pyroglutamic acid, so it has rich acidity, and because it also contains lactic acid, it has a refreshing sourness. It is thought that this is due to the fact that the amount of rice used is about 5 times as high, and the fermentation/aging period is long.

　In the manufacturing process, high polishing rate rice (the starting material) is first washed, simmered, and cooled, then yellow Aspergillus seed koji is sprinkled on top to make rice koji for 3 to 4 days. After making steamed rice, the rice koji, steamed rice, and water are mixed in order in porcelain pots outside, and finally, special rice koji which produces large numbers of spores is sprinkled on top. After fermentation for at least 6 months or more from preparation and further aging for over 6 months, it is then ready. The three processes of saccharification, alcohol fermentation, and acetic acid fermentation proceed naturally in one container. It is a rare manufacturing process even from a global viewpoint.

　Looking at the production site topographically, it faces the Kinko Bay on the shores of the Makinohara plateau in the northeast, characterized by a temperate climate without the north wind and with little frost in winter. The environment is ideal for the growth of microorganisms as it has a warm climate throughout the year, and a small difference between highest and lowest temperatures.

　The pot used for preparation has a diameter of 40 cm, a height of 62 cm, and a capacity of 54 L. This shape has not changed since ancient times. The old pots that can still be seen today were fired in the Narashirogawa, one of the representative kilns of Satsuma-yaki (traditional pottery in the Kagoshima region). In the early 1800's when the production of black vinegar started, this pot was fired as a daily food pot in Satsuma, which means there was a jar suitable for preparing and fermenting black vinegar close at hand.