Koji Fermentation

An experimental process borrowed from Japanese food science: coffee cherries or beans are inoculated with koji — Aspergillus oryzae, the mold used to make sake, miso and soy sauce. Koji enzymes break down larger starches into fermentable sugars and produce amino acids and glutamates, which can add savory depth and an unusual, often umami-tinged sweetness to the cup. The method has drawn attention because it can add value at origin without expensive equipment, requiring primarily the culture and careful control of humidity and time. It remains rare and highly variable between practitioners. Flavor tendencies: unusual savory-umami depth alongside sweetness, with higher perceived complexity.