Tempeh Fermentation

Tempeh fermentation is the process of culturing whole soybeans with mold to bind them into a firm, sliceable cake used across Indonesian cooking. The soybeans are softened by soaking, dehulled and partly cooked, then inoculated with Rhizopus mold, most commonly Rhizopus oligosporus or Rhizopus oryzae. The inoculated beans are spread in a thin layer and left to ferment for roughly one to one and a half days at a temperature around thirty degrees Celsius, during which the mold's white mycelium grows through the beans and knits them together into a single firm mass. Tempeh is typically harvested after about two days of fermentation, recognized by its whitish color, firm texture and nutty flavor.