Place 500g organic soybeans in a large pot and cover with water. Bring up to a boil and then simmer for 3 hrs (if starting from dried) or 1.5hrs (if soaked overnight in cold water).

Meanwhile, mix together 500g rice koji* with 150g sea salt and set aside.

The soybeans will be ready when you can easily mash them with your fingers. Drain and let cool. 

Coarsely mash the beans, either in a food processor or by hand. The paste need not be smooth at this point.

Add the koji/salt mixture to the bean paste (making sure the beans are at room temperature, otherwise the fungus in the koji will be killed). Mix well using your hands and form into large balls (around 6).

Place in a double-layered ziplock plastic bag, flatten a bit and seal shut,

Place in a dark place, preferably warm. (I keep mine in a cupboard above the stove). Once or twice a month turn the bag over and rub it in places. 

For white miso, your paste will ready to use in 3 weeks, 3 months or so for darker miso.

Once ready, remove the miso from the bag and blend in a food processor till smooth. Transfer to a plastic container, and refrigerate.

Makes 2 kg miso.

* Rice that has been inoculated with a fermentation culture into a form of rice malt. It can be bought in dried form in Japanese supermarkets and looks like this.