Authentic miso and shiokoji involve a double fermentation process, using the already-fermented koji as a starter, which is then fermented again with the soy bean, rice and salt.
It is the fermentation process that gives both foods their extraordinary healing properties. They become full of bacteria and enzymes that help digestion and keep bowels healthy. The koji bacteria generates substances that gives miso a radio protective effect. The longer the fermentation, the better it works. You get different colours of miso depending on the type of rice or grain, or how long its been fermenting for. Generally, the lighter the colour, the more mild the flavour. After 2 years’ fermentation, we consider this type of food a medicine.
With miso, the fermentation radically alters the chemical properties of the soy bean, changing it from an oestrogen-mimicking food (containing isoflavones) to an anti-oestrogenic food (breaking down isoflavones daidzein and genistein) assisting your digestive tract to access the health benefits of soy.
The fermentation also produces lots of natural Glutamic Acid, which detoxes ammonia from your brain and body, promotes urination, and stimulates the brain. It also suppresses or reduces fat build up, purifies the skin and reduces blood pressure. High levels of ammonia can cause brain damage and muscle fatigue.
Glutamic Acid is also the core ingredient of Umami – an intense sweet or salty taste that features in a lot of Japanese cuisine and gives miso and shiokoji their richness.