Miso

Fermented soybean paste. Made by inoculating cooked soybeans (sometimes with rice or barley) with koji mold and letting time do the rest — anywhere from three months for the pale shiro to three years for the deep, almost meaty aka.

Miso is best treated as a finishing ingredient. Boiling it dulls the live cultures that give it most of its character; it should be whisked in at the end, off the flame.