Day 1: First Time Miso Making

If you are wondering how to make miso (not the soup, but what you need to make the miso soup with) on your own, you are on the right page.

I was on an around-the-world trip with my husband for more than 2 years, making miso soup to who we have met in the world just for fun.

Having shared this story with my friends in Japan, they always ask me this question.
“So do you make miso on your own too?”

Well not yet! We just came back from the trip last year and haven’t had a chance yet. Making miso at each household was a popular thing to do until my grandmother’s generation. Unfortunately today only people who are serious about gastronomy make miso at home.

So here I am, making my own miso for the first time!

Let’s find a good source

We can access to many Japanese blogs and books writing about how to make miso.

The book that I got information from is this. It is in Japanese.



posted with amazlet at 17.01.07

(*This book is good because everything that the author tells is what she has experienced through making fermented foods. )

There are 2 steps to make rice miso home. 1: Increase the rice koji, and 2: Ferment the soybeans with the rice koji that you made at the step 1.

Step 1 Increase the Rice Koji

You can buy rice koji as much as you need to make the miso. However, I am going to make brown rice koji from a small portion of a packaged white rice koji by adding brown rice.

In Japan, you can buy a pack of koji at a regular super market. I fond some that look ok on

Incidentally, when we say rice koji, like are all these three products listed above, it means that the koji fungus is grown on rice. Miso is always made with soybeans plus some sort of koji, that is grown either on rice, soybeans, or barley. If rice koji is made of the koji fungus that is grown on rice, soybean koji is of soybeans, and barley koji is of barley. The rice koji makes the miso, “rice miso”. Likewise, if the miso is called “Soybean miso”, it is made by soybean koji to ferment the soybeans. Barley miso is made by barley koji to ferment the soybeans. Clear??

Here is a very good explanation by Marukome Miso Company but unfortunately in Japanese.

Step 2 Ferment the Soybeans with the Rice Koji

You are combining the soybeans and the rice koji that you made at the Step 1. In often cases, especially for the first timers, it is easier to buy the packaged rice koji for all what you need than producing rice koji from the starter. Let’s try this though since it is more fun! You can even make brown rice koji from a portion of white rice koji starter too.


Step 1 Increase the Rice Koji with Brown Rice


  • Packaged rice koji: 175g
  • Brown rice: 450g

*It should result in about 800g of brown rice koji.

<How to Make rice koji ①Steam the Rice>

  1. Process the brown rice in a food processer for only 30 seconds or so to give the surface fine scratches. This is for the koji fungus to grow faster.
  2. Wash and rinse the rice really well.
  3. Leave it in the water for 12〜16 hours. If summer, 12 hours and winter, 16hours.
  4. Drain the water.
  5. Bring the water in a food steamer to boil. Place a piece of cloth in the steamer on which you can place the rice.
  6. Steam the rice for about good 2 hours. Mix the rice twice or three times during the 2 hours to cook evenly. At the end, you want to have the rice cooked inside but not so soft that you are happy to eat.
  7. Take the rice out to the biggest bowl you have and cool it down to 30-35 ℃ (86 – 95 ℉) by fanning.
  8. Mix the rice koji into the rice evenly.

…It already took up about 20 hours to go through all the process and we are not even done yet.  This is a whole weekend project.

Anyway, let’s move on.

<How to make rice koji ②Grow the koji fungus>

  • Day 1: Put the new rice koji into a deep pot with a cover for keeping some moist in. Wound a piece of towel around the cover so that a water drop wouldn’t hit directly the rice. Try to keep the temperature as warm as 24-5℃ (77℉).
  • Day 2 ①: Make sure that you see white powder looking mold is growing on the surface. Wait for more if yet.
  • Day 2 ②: Take the new rice koji out to a big bowl to cool it down and mix. Cover the bowl with a big plastic bag and make sure that the plastic is not touching the rice koji.
  • Day 3: Make sure that the white stuff has grown more. Take the plastic bag off to let it breath and cool down.
  • Day 3-4: Make sure that the temperature is coming down and then it is finally done! It is ok that the color is not white as white rice koji.
  • Don’t be so precise about the hours or the number of the days, but what is more important is to observe if it is ready to go on to the next process.

This is the end of rice koji making process. It needs about 5 days in total! You are one step closer to make the miso!


Step 2 Ferment the Soybeans

Soybeans 750g
Brown rice koji (which is just listed above) 750g
Natural salt 350g

<How to make>

  1. Mix the salt with the brown rice koji.
  2. Soak the soybeans in the water overnight. Cook them in boiling water or steam until softened. Don’t throw out the water that you used here. It will be used later.
  3. Take the soybeans out and make it into paste by a big mortar or a food processor.
  4. Mix the rice koji from 1. and the soybeans from 3., then add the water that you used in 2. to make it soft. Rice koji is going to suck up the water, so you can make it softer than a packaged miso.
  5. Place a saran wrap on the surface first, then a plate, then a stone weight which is about double the weight of the whole ingredients. Store it in a cool, dry and shady place for a month.
  6. See if the water is coming out from the miso after a month. Mix it to ferment evenly. Add water if needed. The water comes out of the miso from having the stone weight on and it is good to have some water in because otherwise the miso can have unnecessary mold due to the contact with the air. Leave it for half a year.

Congratulations.This is it for the preparation! Just wait for the fall to come. 😃


For your info
Tomokoji, literally means “friend” koji: It is a method to increase the amount of koji by mixing the starter koji with a grain like rice.

Shiokirikoji, literally means “Salt terminating” koji: It is a method to save the koji by adding salt, so that the further fermentation won’t occur. For example, if you are making miso with 2kg of soybeans, 2kg of koji, and 1kg of salt, then you can mix 1kg of salt into koji now to save, but don’t add any salt in the future when making miso.