Making Miso Paste

We live in a culture that wants to rush the microwave. Everything needs to be immediate and satisfying. This recipe laughs in the face of fast food. But as Ashley says, “It’s well worth the wait.” How long? You need to keep reading to find out.


Miso paste is a traditional Japanese fermented bean paste used to add intense umami (or savory) flavor to all sorts of recipes from soups to sauces, to modern fusion cuisine like garlic miso glazed salmon or miso sweet potato pie.  Vegan cooks love it because the culture used is a B12-synthesizing lactic acid fermentation culture that produces an essential nutrient that’s often lacking in a vegan diet.

To make miso paste at home is simple and easy but it takes at least six months to ferment and most often a year or more is recommended.  If you have the patience, it’s well worth the wait.  Miso can be quite expensive, as much as $10 per cup, and the ingredients to make it yourself cost only pennies.  Making miso at home also lets you control the inputs, and experiment with Americanized versions, such as chickpea or black bean miso, to subtly change flavors and expand your cooking horizons.

To make miso at home you’ll need to acquire a specialized inoculated rice culture, called koji, which is easily available on Amazon.  Koji is a rice or barley substrate that has been inoculated with Aspergillus oryzae culture.  The same culture is used to prepare rice for making sake and rice vinegar, and the culture is also added to soy beans and wheat to make traditionally brewed soy sauce.  You can also inoculate your own rice and start the culture at home but it adds to the time and risk of making miso at home. Most people begin with inoculated rice because it is easily available online or at specialty Asian markets.

How to Make Miso Paste at Home

A Miso Paste Recipe


• 200 grams Rice Koji (available here)

• 250 grams Dry Soy Beans (just over half a pound, or roughly 1 cup)

• 100 grams Salt


  1. Soak the soy beans overnight to soften. In the morning, drain the beans, reserving 1/2 cup of the soaking liquid for later use.
  2. Cook the soy beans until soft. This should take roughly 4 hours on a stove top at a slow steady boil. Be sure to check them periodically for doneness and add water if necessary to keep from burning.
  3. Allow the soy beans to cool completely.
  4. Once the soy beans are cool, mash them into a rough paste. Do not use a food processor or stick blender as the result will be too smooth.
  5. Mix the salt and rice koji thoroughly, breaking up the Koji as necessary.
  6. Add the mashed soy bean paste to the koji, along with the 1/2 cup of reserved soaking water. The result should be a soft play dough consistency that easily forms into balls.
  7. Pack the miso mixture into a fermentation vessel. Cover with plastic wrap, sealing along the surface of the beans to eliminate any air. Apply a glass weight.
  8. Place in a cool dark place such as a basement or closet for at least six months in very warm climates, or at least a year most places.
  9. Remove the seal and enjoy!


If you don’t think you can wait six to 12 months for miso paste, the Fermentools blog has recipes that take as little as three days. But, of course, you’ll miss out on this adventure.


Ashley is an off grid homesteader in central Vermont. She is passionate about fermentation, charcuterie and foraging. Read more about her adventures at

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