Make sure you remove the soybeans from their pods before you soak them. If your market makes a distinction between soybeans (mature beans) and edamame (young, softer beans), use the soybeans. To wash the soybeans, place them in a colander and rinse them under cold water. Pick out any beans which seem shriveled or discolored.
You can also use a pressure cooker to cook the soybeans more quickly if you like. Place the beans in the pressure cooker, add about 1 cup (240 mL) of water and close the lid. Place the pressure cooker over high heat, then reduce the heat when the pressure cooker begins to whistle. Cook the soybeans for about 20 minutes.
Read the packaging to determine the amount of koji starter you should add, as it may vary by brand. If your soybeans were still warm when you mixed them with the flour, cool the mixture to about body temperature before you add the starter.
After the 2 days have passed, move on to fermenting in a brine mixture. Choose a spot where the koji won’t be disturbed as it ferments. The kitchen is ideal if you can handle the smell — try placing the tray in a kitchen cabinet or on top of the refrigerator.
As the koji ferments, it will probably produce a strong odor, so keep it covered tightly when you’re not stirring it.
Discard the solids from this process.
The finished soy sauce should last for up to 3 years if it’s sealed and 1-2 years in an opened container. [7] X Research source
