Fermented Miso Recipe

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Fermented MisoMakes 8–10 cups | 4 hours active time


13 ounces dried soybeans (though, of course, fresh ones would be tastier)
1 20-ounce tub koji rice
7 ounces salt
1/4 cup dry white wine


Start with the dried soybeans, which are available in most markets with Korean and Japanese products (in Seattle, Central Market). Wash beans at least 4 times, until the water runs clear after soaking the beans in a new bath of water (much like rinsing rice).

Put soybeans in a large pot filled with water several inches above the beans. One recipe calls for adding three times as much water as the weight of the beans, but the important part is to make sure the beans don’t dry out. Soak the beans for 18 hours, checking at intervals to make sure the beans are absorbing water and expanding and that the water amply covers the beans.

Once the beans have expanded, drain and add them to a large pot. Add fresh water until beans are covered by more than an inch of water. Bring beans to boil, lower the temperature, and simmer for four hours. (You can also cook the beans in a pressure cooker, in which case the beans can be cooked in about 20 minutes.)

During the cooking process, the beans will emit a protein-rich foam, saponin, which can be skimmed off for another use. Once the beans become soft enough to squeeze between your fingers, they are ready for the next phase.

After draining the beans, you can refrigerate them and continue the process the next day. Otherwise, once the beans have cooled to room temperature, move on to the next step. (NOTE: Make sure that the beans return to room temperature; if they are too warm, they may kill the koji.)

Mash the soybeans into a paste using a food processor. The degree of mashing is left up to the discretion of the miso maker; some misos are chunkier than others, though a miso that has larger bits of soybean may take longer to ferment.

In a large bowl, mix the salt and koji rice together. Take particular care to distribute the salt well so the koji will ferment as evenly as possible.

Add the mashed soybeans to the koji-salt mixture, taking care to mix the two well, kneading and folding it several times to distribute the salt and koji throughout the soybeans. Once the ingredients are thoroughly combined, form small balls with the mixture, a bit larger than a golf ball. Take special care to squeeze as much air out of the balls as possible: the fewer pockets of air in your miso container, the less opportunity for miso to grow unhealthy mold.

Find 2-3 four-quart containers to ferment the miso in. Wide-mouth jars with an airtight lid are preferable. Avoid potentially toxic plastic or metal containers that may affect the taste of the miso. Although miso should be strictly shielded from the sun to prevent the sun’s rays from killing the lactobacillus bacteria, Cafe Juanita uses glass jars to better observe the ongoing changes in color during the fermentation process.

Before adding the miso balls, lightly spray the already sterilized jars with white wine. This step adds another layer of disinfectant that discourages the formation of harmful germs during the fermentation process. Coat the entire jar. You can also dust the bottom of the jar with salt for the same result.

Add miso balls to the jar, pushing them hard against the jar. Again, the goal is to remove as much space and air in the miso paste as possible to prevent the growth of mold. Once all the miso balls are in the jar, press the mixture down several times with your hands, packing it as tight as you can. Even out the top of the miso, making sure the surface is mostly flat. Spray a little bit of the wine along the top sides of the jar and across the surface of the miso (or a light dash of salt for similar effect). The presence of alcohol or salt discourages the growth of harmful mold on the miso.

Drape a paper towel lightly soaked in water across the top of the young miso paste. The towel functions as a disinfectant and also provides a way to sop up the thin layer of moisture that occurs during fermentation.

Before sealing the jars with a tight fitting airtight lid, place a weight on top of the miso. A heavy pie weight would work, or you can pour salt into a plastic zip-close bag and place it on top of the miso. The plastic bag fills the space in between the miso and the top of the jar, packing most of the remaining space (the goal being to provide as little area for mold to grow as possible). Once jars are as stuffed as full as possible, seal the jar and then use thick packing tape to secure it further. Once the jar is prepared, stow it away in a dark place and let the fermentation commence.

Warmer temperatures accelerate the fermentation process. Fermentation can take anywhere from six months to a year, though a longer wait may be rewarded in a more full-flavored and delicious miso.

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