Kiri-kaeshi (First turning)
Kiri-kaeshi (Turning koji)
Japanese: 切り返し（きりかえし）
Mixing koji to equalize temperature and moisture. Performed in the first half of koji making.
The first care step, performed 10-12 hours after inoculation when koji mold begins generating heat. Clumped koji is broken apart to eliminate temperature and moisture unevenness.
Koji mold generates heat as it grows; without intervention, center temperatures rise excessively. Turning equalizes everything and supplies fresh oxygen. Warmth and moisture felt by hand guide the next decision. Neglecting this risks 'burnt koji' with weak enzyme power affecting miso flavor. Nighttime turning is demanding but essential for protecting koji quality. Timing is learned through experience and records.