Miso

Miso is made by cooking a grain or legume—usually rice, sometimes barley, sometimes soybean—and fermenting it in shallow trays with koji starter for several days to develop enzymes. The resulting koji is then mixed with ground cooked soybeans, salt (5–15%), and a dose of an earlier batch of miso (to provide bacteria and yeasts). In traditional miso making, the mixture is allowed to ferment (and eventually age) in barrels for months to years at a warm 86–100°F/30–38°C. Various lactic acid bacteria (Lactobacilli, Pediococci) and salt-tolerant yeasts (Zygosaccharomyces, Torulopsis) break down the seed proteins, carbohydrates, and oils and produce a host of flavor molecules and flavor precursors. Browning reactions generate deeper layers of flavor and color.