Freezing
Japanese: 冷凍保存（れいとうほぞん）
Freezing miso to completely halt fermentation. Most effective for long-term storage.
Freezing stores miso below -18°C. At this temperature, microbial activity and enzyme reactions nearly completely stop, preserving the flavor from preparation time for extended periods.
Due to high salt content, miso does not freeze rock-solid in home freezers. It stays scoopable, so you can take what you need. Using freezing and refrigeration together, you can enjoy miso at different aging stages simultaneously. Freezing is a technique for 'stopping time.' Freezing at 3 months, 6 months, and 1 year lets you compare aging later. As a growth record, the freezer serves as a time capsule.