Stationary phase
Japanese: 定常期（ステーショナリーフェーズ）
The period when microbial growth and death reach equilibrium and cell numbers remain constant. Caused by nutrient depletion and metabolite accumulation, often accompanied by active secondary metabolite production.
The stationary phase is when growth and death balance, keeping total microbial numbers roughly constant. Nutrients are depleted and metabolic products (acids, alcohols, etc.) have accumulated, making further growth difficult.
What is fascinating is that secondary metabolite production becomes active during the stationary phase. Microbes that have stopped growing begin producing substances like antibiotics and pigments as survival strategies. The increasing flavor complexity during fermented food aging is partly due to stationary phase metabolic activity.
Considering long-term miso aging, the log phase is merely the opening act. During the long stationary phase and beyond, the accumulation of microbial metabolites and chemical reactions shape miso's deep flavor.
The stationary phase is not an ending but the beginning of deepening.