Miso is a bean paste made by mixing beans (soybeans traditionally), salt, and koji, a grain (usually rice) which has been inoculated and fermented with a mold, Aspergillus Oryzae. The flavor and complexity of miso is unmatched even compared to other fermented dishes. It is at once umami (savory), sweet, salty, and powerful.
There are many varieties of miso, from sweeter “white” misos (which are less salty and ferment for a few weeks), to this “red” miso (akamiso) which is salty, and measured in YEARS of fermentation. The reddish brown colors occur due to bacterial action and enzymatic processes that occur during miso’s long fermentation. A summertime is considered a year, so if you make a miso in February and finish in December, it is a “one-year” miso.
During the process, brine called tamari (from the Japanese tamaru, literally “collect” or “puddle”) is usually expressed. It can be drained off and used separately as a flavoring agent. Traditionally, miso makers would never sell the tamari from their miso, instead keeping this highly coveted treat for themselves. (Once you’ve had tamari harvested from your own miso, you will know why!)
It can be used in miso soup, as a marinade, in salad dressings, etc.
Koji, enzymatic powerhouse
The most practical way to make your own miso is to first buy koji, a grain (rice or barley) which has already been inoculated with the mold culture. (It is difficult, but not impossible, to make your own koji.) Local Asian markets usually carry dried koji. You can also find koji from online merchants like this one.
If this all seems too daunting (especially if you are looking to make miso), You can purchase pre-made koji online, or find it at a Japanese grocery store. This form is usually dehydrated (aka firm dried granular koji).
If using fresh or homemade koji (good on ya!), use 28 ounces koji rather than 20, and 1 cup ounces soaking liquid (instead of 1 1/2c), as there is more moisture from fresh koji and less is required to rehydrate the grains.
This recipe is for a long red miso (akamiso) style and in this version, I made it with adzuki beans rather than soybeans.
You want to shoot for about 710 grams of beans cooked. In my tests, different beans end up with varying levels of hydration. So if you’re using one of these beans, you can start with the following DRIED bean weights:
- Soybean: 368 grams (193% increase during cooking)
- Azuki: 430 grams (165% increase)
- Chickpea: 332 grams (214% increase)
- Peanut: 483 grams (147% increase)
- 400-500 grams (about 2 cups) dried beans (chickpea, adzuki, or other legume)
- 315 grams (about 2 cups) dried firm granular koji OR 360 grams fresh koji
- 160 grams (5 oz. by volume) fine sea salt
- 15 grams (about 1 Tablespoon/10 ml) mature miso
- filtered water
- half-gallon or larger glass or ceramic vessel
- jar or wine bottle which fits inside mouth of vessel
- paper grocery bag, or tight-woven canvas or cloth bag (in which vessel can fit)
- masking or packing tape
- Soak beans in 3 times the weight of filtered water overnight (up to 24 hours).
- Drain beans from soaking liquid.
- Bring ½ gallon (2L) of filtered water to a boil, then add beans and reduce heat to simmer. Cook until soft (cooking time varies by bean).
- Drain beans over a colander placed over a bowl or container to capture the cooking liquid. Add beans to a large mixing bowl.
- Dissolve salt in 400 ml (14 oz.) of the cooking liquid you reserved. If using fresh koji, cut this in half (half the salt and half the cooking liquid). Let brine mixture cool down to 100°F/38°C.
- Mash the beans, leaving about ¼ of the beans intact.
- Add mature miso to the beans. Stir until it is incorporated.
- Once bean mixture has cooled down down to 100°F/38°C, add the warm brine and then stir in koji. Mix well for 10 minutes. The koji will absorb the cooking liquid.
- You should be able to make balls with the mixture. If it crumbles in your hand, add more of the cooking liquid.
- Sprinkle water on the inside walls of the fermenting jar/vessel, then quickly add sea salt to the bottom and sides so it sticks to the inside of the jar.
- Pack the vessel with the mixture, ensuring there are no air bubbles in the jar.
- Once packed, tap vessel on a towel or wooden cutting board several times to ensure that any air bubbles in the mixture come to the surface.
- Add remaining salt to the top layer of the mixture.
- Add a weight such as a glass bottle or plate to the top of the mixture. This will weigh it down and allow the tamari to rise to the surface during fermentation.
- Carefully place the vessel into a paper or canvas/cloth bag. Staple and/or tape it shut so no insects can enter. Write the date on the bag.
- Store it in an unheated space for at least six months (until next cool season), and over one summer. You can ferment as long as 24 months.
- Carefully open the bag and remove the vessel.
- Remove the weight. Scoop offt any funky mold from the top surface.
- Blend into a smooth paste using a blender, food processor, etc.
- Pack contents into a glass jar. If using a metal lid, store with a layer of parchment paper between the metal lid and the lip of the jar.
- Store in the refrigerator. Lasts several years
The making of miso…
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To learn all about this wonderful Japanese culinary tradition, pick up The Book of Miso by William Shurtleff.