In 2025 the Bega Valley Seed Savers ran the ‘From Soybeans to Miso‘ as part of the ongoing ‘From Seed to a Feed‘ activities. The notes below were provided to participants who had grown their soybeans from seed over the summer and were joining one of the workshops to learn how to make their own miso from their home-grown soybeans.
What is needed to make miso?
There are only 3 ingredients in traditional miso: soybeans, koji and salt.
You will also need some kind of fermentation vessel, which can just be a reused jar. Optionally you may also want to put a weight on top of the miso while it ferments.
Soybeans
Miso is traditionally made with soybeans. They are soaked and cooked before they are mashed with the other ingredients. Dried soybeans can be purchased from your local wholefoods store or home-grown. Some varieties are specifically bred to make products like miso or soysauce from, where are others are meant for eating in meals. When purchasing from a wholefoods store in Australia it is unlikely that the specific variety name or intended end use will be given. So home growers have a better ability to make sure they are growing a variety specifically intended for miso making. However whether you can tell the difference between different soybean varieties in your home-made miso will depend on your palate and experience.
The same process can be used to ferment any dried legume, eg. navy or kidney beans or chickpeas, although these are usually called ‘modern misos’ or ‘tasty pastes’ or some other name that makes it clear they aren’t traditional soybean miso.
Koji
Koji is traditionally rice that has had a fungus grown on it. The fungus does not produce mushrooms but grows a fine white mould on the rice, which looks somewhat similar to the mould on camembert or brie cheeses. The fungus used is Aspergillis oryzae.
Other grains other than rice can also be used to grow the A. oryzae. Barley and millet are suggested alternatives, but buckwheat, rye, qinoa and others can be used.
Koji can be made at home from scratch or can be purchased in dehydrated form either online or from your local wholefoods store.
Salt
Chose a salt that does not have iodine or free flowing agent. Iodine is an anti-bacterial and may interfere with the fermentation process. Salts with other minerals in them like Himalayan pink salt are fine to use.
Lower percentages of salt are used for sweeter white misos that are ready faster. Long ferments for darker misos use more salt.
Day Before
Weigh out 125 grams of soybeans.
Wash and rinse your beans well. Leave them to soak in at least 4 times the volume of water to beans. You should soak your beans for at least 12 hours, but ideally 18 to 20 hours. Do not soak for more than 24 hours. Soaking time is dependant on your beans and their age.
You can change the water during the soaking time if you desire. It may help but isn’t critical.
Morning of Workshop
Rinse your soaked soybeans and cook them in fresh water. Cook your soybeans until they are soft enough to squash easily. You can steam, boil or pressure cook them. We will be mashing the beans so we need them quite soft but not watery mush.
After cooking please drain but do not rinse the beans.
If you have finished cooking them more than 60 minutes before the start of the workshop (2pm) please put them in the fridge. Normal food safe handling does apply and they should not sit around at room temperature for more than 2 hours before being made into miso. They do however need to cool to room temperature before being added to the other ingredients.
Boiling Option
Cover the beans with at least 5 cm of water in the pot. Put on a lid and bring to the boil. Boil for 10 to 15 minutes. You can skim off any foam that appears.
Reduce the heat to a simmer and continue to cook until the required tenderness is reached. This could be as little as 45 minutes to 1 hour or up to 4 hours for older beans. You may need to top up the water every hour.
Steaming Option
Use a steaming basket in your pot to hold the soybeans above the water. Bring to the boil with a lid on and boil for 15 minutes. Reduce the heat and continue to cook until the required tenderness is reached. You may need to top up the water during the cooking period, if so add warm or hot water when required. Steaming will take longer than boiling.
Pressure Cooking Option
Fill the pressure cooker to the minimum marked water level, usually about 5cm. Place beans in a steamer basket inside the pressure cooker. Cook for 30 minutes at 15psi (High/Max) or 45 minutes at 10psi (Low/Med depending on brand).
Check they have reached the desired level of softness and continue cooking either with or without pressure if required.
At the Workshop
Step 1: Rehydrate the koji.
- We are using a dehydrated koji product, rather than making it fresh.
- Add 25ml water to 100g of dried koji (equivalent to 125grams fresh koji).
- Allow to absorb for 30 minutes.
Step 2: Weigh out 30 grams of salt and add it to the koji.
- We are making a medium miso, which will be ready in about 12 months and is made with 12% salt.
Step 3: Mash soybeans.
- Mashing can be done in several ways: with your hands; with a potato masher or fork; or the ingredients can be put through a grinder.
- It is your preference whether you leave it very chunky or well mashed. The resulting miso can also be processed to a smooth paste after maturity too.
Step 4: Mix koji and salt into the mashed soybeans.
Step 5: (Optional) Add miso from a previous batch as starter culture.
Step 6: (Only if necessary) Add cooled, boiled water to get required consistency.
- Add a little (1 Tbsp) at a time and mix well before adding more. Use as little extra water as possible.
- Soybean cooking water (cooled) can also be used but only if it is used promptly and not left sitting around.
Step 7: Prepare the fermentation vessel.
- Ensure it is sparkling clean.
- Rinse out with boiled water. Pour out any excess.
- Sprinkle the inside of the jar with a little salt and shake around to stick to the sides.
Step 8: Pack the miso into the jar as tightly as possible.
- Remove any air bubbles.
Step 9: Sprinkle a little salt on the top, particularly at the edges where miso meets jar.
Step 10: Add a weight or use extra salt.
Step 11: Cover with a cloth or loosely applied lid.
When Can I Eat It?
We have made a medium miso which will be ready at about 12 months or when it’s to your taste.
You will see tamari fluid gathering on the top of the paste as it ages. You can remove some of this for eating but it adds lots of flavour so should not all be removed. It can be mixed back into the miso.
You may prefer your miso to be very smooth. You can pass the finished miso through a grinder or a food processor if you want. Or leave it chunky if you prefer.