Organic acid
Japanese: 有機酸
A general term for carbon-containing acids, including citric, lactic, and acetic acid. The source of acidity and preservative power in fermented foods.
Organic acids—lactic acid, acetic acid, citric acid, succinic acid—are carbon-containing acids. They are both the source of sourness in fermented foods and crucial substances enhancing preservation.
Lactic acid from lactic acid bacteria, acetic acid from acetic acid bacteria, citric acid from black and white koji molds—each organic acid gives its respective fermented food a unique acidity.
By lowering pH, organic acids suppress spoilage bacteria and extend shelf life. Sourness is simultaneously 'flavor' and 'defense.' The role of acidity in fermented foods transcends taste alone. When you detect a subtle sourness in miso, it's proof that fermentation has progressed steadily.