FermentingProcessing & Food PreservationRecipes

Making Miso

Mashing cooked soybeans

It is now the middle of winter here in Japan and time again to make another year’s supply of miso. The deep flavour of miso soup (misoshiru) remains for many in Japan a daily dish. Traditionally the first meal of the day consisted of a steaming bowl of miso soup, a bowl of rice, and a selection of pickled vegetables. It is an excellent breakfast that will likely see a resurgence with the demise of industrialized agriculture and global food transportation.

The current trend for bread breakfasts (fluffy, sweet, white bread), the wheat for which is mostly imported, is occurring at a time when Japanese farmers are receiving subsidies to grow less rice! The health cost of this dietary shift will, no doubt, also soon become apparent. The simple diet of whole grains, fermented beans – in the form of miso, shoyu (soy sauce) and natto – vegetables, seaweeds, fish and very small quantities of meat has served the Japanese well for hundreds of years. The Japanese have the longest life expectancy of any nation in the world and, most importantly, in general remain in good health well into their final years.

Mixing koji and salt

Miso is now enjoyed throughout the world and is widely recognized as a healthful, nourishing addition to the diet. It is also easy to make so we can all enjoy wholesome homemade miso made from local organic ingredients.

Mixing koji and soybeans

A nitrogen fixer, the soybean is an excellent plant to grow to help maintain fertility in the garden. An old practice, less common now but still in use in some parts of Japan, is to grow soybeans around the edge of the rice paddy. The two plants are believed to make good companions, particularly as regards their mutual influence on insect levels. They certainly go well together as a meal!

Although soybeans are the traditional ingredient of miso, almost any legume can be used. I have sampled excellent miso made from chickpeas, lentils and fava beans.

Forming mixture into balls

Miso is made by combining cooked soybeans or other legumes with the koji mould (Aspergillus oryzae). The koji is typically grown on rice and is often available from Asian food markets in this form. It is also possible to purchase koji culture which can then be grown on to a medium such as rice, barley, other grains or legumes. Unfortunately domesticated koji is not an easy mould to keep going (unless you have a sterile lab to work in) so with either of these methods it will be necessary to purchase more koji each time you wish to make miso. Even so, it will be much cheaper (and more fun and satisfying) to buy koji and make your own miso than it will be to buy packaged miso. (In Japan there are traditional methods of “wild fermenting” miso, without the addition of domesticated koji, which I will discuss in a future post).

Throwing balls into fermentation vessel

Miso comes in a wide variety of flavours. Altering any step of the process — any ingredient or the ratio of ingredients, the length of time the miso is left to mature — will give a distinctive colour and flavour to the finished product. In Japan such differences have become regional specialities: the island of Kyushu is known for its barley miso (koji is bred on barley rather than rice), the Tokai region for using no grains at all (breeding the koji on beans), and in Nagoya a dark deep flavoured miso is made by maturing the miso for three years. Using more koji will produce a sweeter miso, left to mature for longer the miso acquires a deeper flavour.

Mixture flattened and salted

Basic miso recipe (makes 5kgs):

Special equipment needed:

Fermentation vessel (pottery, enamel, glass or food grade plastic).


  • 1.3 kg soy beans (or other legume)
  • 1.8 kg koji
  • 650 g salt
  • water


  1. Soak soybeans overnight before cooking. The heat source used for cooking will alter the flavour of the finished product as will the water source. In Japan it is believed that wood fires and spring water produce the best miso. Cook the beans until very soft. After cooking strain the soybeans and keep the water for later use.
  2. Mash the cooked soybeans and place in a large mixing bowl.
  3. Mix koji with 50 grams salt.
  4. Mix koji through mashed soybeans.
  5. Water left over from cooking the soybeans is now slowly added to the soybean/koji mixture to achieve a good consistency. The consistency is tested by forming the mixture into a ball and throwing it against a hard surface. If the ball cracks up or crumbles the mixture is too dry, if it splatters everywhere it is too wet. After achieving the correct consistency all of the mixture is rolled into balls.
  6. The fermentation vessel should be cleaned with white alcohol or strong antiseptic herbal tea.
  7. Throw the balls into the pot. The aim here is to remove any air pockets within the pot. When all the mixture is in the pot press to form a flat surface.
  8. The remaining salt (600 grams) is now sprinkled over the surface, especially around the edges as this is where uninvited moulds will first make their appearance.
  9. Cover with bamboo leaves or cling film – again taking care to cover the surface right up to the edges – to help prevent moulds from forming.
  10. Wait. The miso can be eaten after six months (if made during the warmer months) but it will be better if left for longer. Often it is left to ferment for one, two or even three years before consumption. As with most fermentation processes temperature is an important factor. Starting your miso in autumn it will likely need more than six months before consumption. During warmer times of the year the fermentation will be faster but so will the chances of competing moulds moving in. Check your fermentation vessel regularly and remove any moulds appearing on the surface. Even if a layer of mould covers the entire surface the miso below should be fine. Just scrape off the surface to a sufficient depth where only mould free miso can be seen.

Finished miso


  1. This looks great & I would love to try it, but a bit daunted by the quantity. Dion, do you have any information if a simple halfing the recipe or less would still work, sometimes particular ratios need to be maintained, cheers julie

  2. Julie, yes, you can simply halve the recipe.
    The first time I made miso I made a very small quantity and after a one year wait I had a very small amount of fantastic miso. I was kicking myself that I hadn’t made a much larger amount. Another year long wait before I would have more!

  3. I’ve heard miso is one of the most healthy and nutritius foods, along with other fermented foods. Can anyone describe/compare it’s taste or smell? (Six months is a little too much time waiting to taste it)

  4. George, it’s a bit unique, so not easy to describe. Suggest you go to a good quality health food shop & buy a small amount of an organic one based on soy beans & that should give you the idea. I use miso as a stock for lots of things, soup, curries, sit fries etc it’s yummy & very very good for you! I can’t wait for the cooler weather & a big bowl of homemade veggie dumpling & miso soup :)

  5. Great post. I particularly found the information on koji interesting. I too recently made my own batch of miso with a group of ladies (obachan) here in Tokyo, and our method varied slightly. We used a ratio of 1:1 miso:koji (2.5kg of each), and 1 kg of salt. We first mixed 800 grams of the salt with the koji, then threw the remaining 200g on top of the cling film still in the bag. They say they prefer it to be saltier, and I think miso is essentially a salty food product. I do like the idea of sprinkling the salt on the surface though. My next mission will be to make natto. yum yum!

  6. Thanks for the comment Mark. As I mentioned in the article there is a lot of regional variation in miso making which also means a lot of room to experiment and a lot of scope for creating subtley different flavours.
    In the basic recipe I have given, even though the majority of the salt is sprinkled on top, the resulting product is still, by western standards, very salty.
    If you’re looking to make natto to you might like to check this out:

  7. I love miso but have been unable to get it after moving deep into the countryside. I have already grown my own koji and do not find it difficult but I am more laboratory minded individual. I made mine for making sake though so I should be inspired by your post to try Miso. I bought a kilogram or more of soybeans a year ago but never got around to cooking them and making miso. Look what I am missing out on :)

    Commercial miso is just cheating, ultra fast fermentation and injecting ethanol and other chemicals to cheat the natural method of traditional culture so I’ve not been inclined to buy any unless I need a misoshiru fix.

    domo arigato

  8. George its like trying to explain Vegemite to foreigners… while you can make a savory broth from it with hot water that use is not prevelant across the population. Miso is a flavourinf ingredient but the soup form includes a fish base, usually from freeze dried Bonita shavings. There is also an extra flavour sense in Japan not in the English lexicon except through the Japanese loan word. So now you know why its harder to describe. Vegemite has it. For my best understanding it easily relates to describing a lot of fermented foods.

  9. Peter, It seems that many westerners would agree that miso is somehow comparable to vegemite as spreading it on toast has become a popular method of consumption! I do agree that the uniqueness of taste is analogous. I must say though that I have never met anyone that didn’t grow up with vegemite that admits to liking it whereas miso seems to have very wide appeal.

    For the benefit of other readers I just want to clarify a couple of points you made in your comments.

    Not all commercial miso’s are created equal. There are many made with industrial processes, as you descibe, but much commercial miso is still made by traditional processes and often by family owned businesses that have been producing it for hundreds of years. Cheap forms you find in supermarkets are likely the former but in health food stores you will often find the latter. Widely distributed macrobiotic brands such as Ohsawa or Mitoku deal in traditionally made miso only. Small, local producers (and there are now many in western countries) will most likely be using traditional processes also.

    Soy sauce is another product that has been greatly altered by industrial processes, to the point where it is often no longer fermented at all. Soy sauce is also easy to make (for the patient):

    Tamari, which is very similar to soy sauce, is a by-product of the miso making process and can be squeezed out of the finished miso paste. Although, this authentic tamari will be much saltier than soy sauce or commercial tamari which is now usually made with the exact same process as soy sauce only without the addition of wheat.

    Miso soup is traditionally made with a stock of (sun)dried bonito fish flakes, konbu seaweed and dried shiitake mushrooms. You are correct that there are now miso pastes being marketed that already contain a fish stock base but these tend to be of the cheap-industrial-supermarket variety. So-called “instant” miso is a freeze dried powder mixture of something that once resembled miso, fish stock and seaweed.

    Something else to note about commercially made miso, and most other commercially made fermentations, is that they are often pasteurized and therefore are no longer “live” foods. It is clear that many of the health benefits of fermented foods come from their containing live microorganisms that build a healthy microbial ecology in the gut. When buying any fermented foods always go for the unpastuerized varieites when available. Even better, make them yourself.

    I suspect that in your sake making you started with a dried/powdered form of pure koji culture that you then grew onto rice, right? This is a process that many people, including myself, use for making miso. This is not the difficult part I was referring to in my article. The difficult part is keeping a pure Koji strain going so you don’t need to keep buying the powdered pure koji or koji already grown on to other substrates. From my understanding, to do this you need a purpose built room where you can filter out all the other millions of yeasts and molds that are present in the air at all times.

    But there are traditions in Japan of using wild koji to ferment miso and this will be the subject of a future article on miso.

  10. Yes, I originally started with dry culture (spores / Koji-kin) and grew them out on rice I do not use the whole dry culture and I do not use the rice in miso or sake production. I use it all to grow new spores / koji-kin which I use in larger quantity to innoculate rice. This way I have a great expansion of spore innoculant that is one generation from the pure sterile sealed strain. I can always go back to the sterile strain to make more spore expansions but so far I have not needed to. If I wanted to, for little money I could build a laminar flow wall in a closet or small room in the house. A high air flow volume electric cage fan on top of a wooden box which has a large HEPA filter mounted to the front of that box is all that is needed. The air flowing out is sterile and by keeping the dirtiest samples down stream and transferring to growth media in the cleaner upstream air is the standard sterile technique. But I don’t find I need to when making my own as my high innoculation rates ensure the koji mould has a head start on other spores.

    This web site has a commercial offering of the flow hood I am describing in case you do not want to build your own:


  11. Thanks for the link Peter. A great resource indeed.

    Thanks also for the information on your koji extension process. I had been told that this process doesn’t work so well for koji so I am very glad to hear otherwise from you. As I write I am in the process of growing some koji culture onto rice in preparation for a new batch of miso so I will definitely try to extend it as you have described. I do have a couple of questions though: how do you keep the culture dormant? Do you freeze it or refrigerate it? And, secondly, what percentage of innoculated rice do you use to innoculate more rice for fermenting?

    1. I just found this thread when I was trying to determine if I could use the soybeans I have just pressure cooked, accidentally, with the lentils I had in the pressure cooker planning to make dal. I forgot the lentils were there. I wanted to determine if I could use the mix and it looks possible. I get my culture from gem cultures and their directions and variety of cultures is great. I always have 1/2 gallon canning jars going with air locks on the top.

  12. Hi Dion ,Peter and a lot of friends
    I started making my own pro-biotic miso without commercialy avialable koji 3 days ago.I used the mixture of cooked rice,milin, suger instead .Three days after mixing,it produced smell like “koji”,so I added Kellogg’s cereals,some water,cooked soy all together and left at room temperature 30+-2c. See how’s go. This was my desparate measure.I want to know about “wild koji”mentioned by Dion on 12Feb12. Yoroshiku. Pharmer Mic

  13. This is such a great recipe. But if you want to make this is great amount of ingredients, you must be able to know how to keep it from mould and other bacteria that can spoil this wonderful recipe.

  14. Jerrif thanks for the comment. As I mentioned in the article any mould that develops will be on the surface only and can simply be removed by scraping the surface. There is no need to buy a product.

  15. Hey i am super keen to make my own miso! I have looked far and wide and cant seem to find a local source of koji. I am a strong believer in diversifying fermentation practices and I am more inclined to attempt a wild miso fermentation as opposed to sourcing a pure koji strain from somewhere far away. Do you think making miso without koji would work? I have fresh unpasteurized miso, and i was thinking of using that to innoculate cooked soy beans.

    1. hey chris, its been 5 years since your post but i wanted to ask you if you could wild ferment miso or if you found more information about it?

  16. Hi! I am new to making miso and my biggest problem so far is finding Koji. I can find Koji-Kin (spores) but after talking with a miso maker in Canada, it seems like making Koji rice is the most difficult step in miso making. I could also be interested in inoculating directly on beans rather than rice. Anyone has basic infos about that?

    As a hint for the previous comment, when going wild you can find yourself with a wide variety of molds, fungus and little crippers ending in your miso…and ferment it! The results could also be just as wild! If using unpasteurized miso as a culture starter, it definitely isn’t that simple. I think you would first need to find a way to make the fungus grow back without contamination. To consider as well is the fact that a finished fermentation means less vigorous yeast or micro-organisms, therefore sluggish or stuck new fermentation. But experimenting is always the key to an unknown path, Keep me informed of any development!

  17. I’m looking for some Koji, dried spore culture or even just a small sample of sterile Koji culture, and I can expend it out from there.
    Can anyone help me out thanks?

  18. Can you give an example of a strong antiseptic herbal tea? Also, is barley miso made from barley along with soy beans, or is it just that the koji is grown on barley.

  19. For antiseptic herbal teas you can use sage, juniper, wormwood, hops, kawakawa…

    Barley miso is made by growing the koji on barley. It will usually contain soy beans although it can be made with any kind of beans. Likewise, brown rice miso (genmai miso) refers to the medium the koji has been grown on.

  20. I made a batch of miso and found some lovely smelling tamari on top… Along with some funky mold. Is the tamari safe to use?

  21. Rose, yes it is safe to use. Just skim the mold off and the tamari will be fine. Same applies if the mold is sitting on the miso. Just scrape it away.

  22. I have some 2-3 year old organic soy beans. Does anyone know if there is any reason they would not work for miso? Thanks!

  23. Thanks! I was in Japantown in San Francisco and found koji, and I’m now ever excited to try making miso for my very first time. Your photos are beautiful.

  24. Koji is available widely on the internet (use Google or other search engine) and it can be bought online and shipped to you. I get it at a local Japanese mercantile store in Denver CO.

    1. I too am looking online for the dried spores so I can inoculate my own rice and other legumes. If you have found some in Canada, could you share? If you haven’t, my next avenue is to contact some Canadian miso producers to ask if they will sell me some of there sprores, or at the very least share the distributer with me. I’ll try to update with any results I come across.

      As a last result I may try growing my own with the assistance of a chemist and some laboratory equipment. I’d prefer to get a perfect start as soon as possible, then start playing around afterwards.

  25. There are tons of places online to get quality starters–you can buy koji starter, and miso making supplies, here’s one link: ww.culturesforhealth.com/soy-cultures-supplies.html. You don’t need to be Mr. or Ms. Science to do this. Also, Sandor Kraut has two books out about making all kinds of things with fermentation, including miso and so forth: http://www.wildfermentation.com/who-is-sandorkraut/

  26. I see this post is from many years ago but I am wondering if there was ever another article on wild fermented miso? I searched through the site for it and didn’t come across it.

  27. I am from kyoto now in chiba, my family has always made miso for own use it is very easy to do and better than store variety nice to see people outside japan trying it. make large batches save time if you follow basic principle and keep clean not much can go wrong. Good luck!

  28. This tutorial is great!!!
    I just got my first koji rice from a friend who had japan trip recently.
    I am so excited.

    I want to ask few things before i start making miso. First, my friend bought me a 300gr package of rice koji, my question is, can i make another rice koji from this rice koji? I mean can i use this koji rice as a starter to make another koji rice just like making natto?

    Second, i heard that there’s chickpea miso and rice miso instead of soy. I understand the making of chickpea miso, procedure is just same with soybean. But how abt using rice? Do we boil and smash?

    Third, can we use big clear glass jar and cover with dark fabric to ferment the miso?

    Thanks so much!!!

  29. The cling wrap on the cap broke through and the salt sunk into the miso. I removed the moldy cap and poured off the tamari. The miso itself has a strong mold taste. Anyone have any tips on how to save this?

  30. I want to try this recipe with Fava beans. I only have about 1lb of cleaned beans, and since the process takes a decent amount of time, I would like to make a whole recipe. Wondering if I can freeze my fava’s until I find more? Or does freezing them completely alter the finished product?

  31. when will you make the post about wild fermenting miso? by wild fermentation you mean capturing koji spores from the air? i have been looking for information about this and there is not much out there :(

  32. Thanks for the details of making miso. I recently saw koji in a store for the first time and a lumpy variety of miso. I didn’t know about cleaning the vessel and throwing the balls. I think I can make it.

  33. I am wondering about storage when its ready… do you just keep it in the fermenter then use portions when you need it? Can you freeze portions and use some a little at a time from a refrigerated container?

  34. Hi, I plan to make miso soon using this wonderful recipe. My question is: How do you mash the soybeans? Is it okay to use a food processor? Can they be mashed by hand? Or is a mortar and pestle required? Thanks!

  35. Dear Dion,
    I am interested in making miso without using koji – I have seen this japanese article https://medium.com/@satoyamalibrary/miso-dama-the-natural-art-of-fermentation-without-using-koji-malt-255afc451bb6#:~:text=Making%20miso%20without%20using%20koji%20malt&text=So%2C%20traditionally%2C%20village%20people%20do,earth%20oven%20in%20their%20houses.
    which is very interesting but it does not have any details about the recipe and process. Have you written yet the article about natural fermenting without koji?
    I am presently experimenting with maangchi’s korean recipe for doenjang which does not require koji but I am concerned that the quantity of salt is too great. If you have written your article on natural fermentation I would very much like to read it. Thanks,

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