Miso is a thick, savoury Japanese paste made by fermenting soybeans with salt and kōji — a grain inoculated with the mould Aspergillus oryzae. Months to years of ageing turn the beans deeply umami, salty and faintly sweet, ranging from pale, mellow white miso to dark, pungent red. A spoonful seasons soup, glazes fish, dresses vegetables and deepens almost anything it touches.