Omoshi (Pressing stone)
Omoshi (Weight stone)
Japanese: 重石（おもし）
A weight on miso applying pressure, blocking air and promoting tamari rise.
A weight applying even pressure to miso surface. Standard: 20-30% of total weight. Pushes out air, reducing mold risk.
Pressure causes tamari to rise, covering the surface for additional air protection. Pickling stones or water-filled PET bottles work. Start heavier, lighten after tamari rises. Too much weight can make miso dense. Check tamari after 2-3 months and adjust. Fine-tuning weight influences the final texture.