Step 1

Gather all the ingredients. Besides this, you will need 2 large bowls (one should be a very big one), 1 strainer, Instant Pot (or pressure cooker or a large pot), a clean cloth, alcohol (shochu or vodka), a potato masher (or a food processor), a 1-gallon glass jar to put miso in, and a bag of 1 kg (2.2 lb) table salt.

Step 2

Gently wash the soybeans thoroughly several times under running water. P.S. The foam seen in the images here is not soap.

Step 3

In a large bowl, add the rinsed soybeans and fill the bowl with filtered water to about 5 inches (10 cm) above the beans. Soak the soybeans for 18 hours.

Step 4

Drain the beans. Look how large the beans are now. The right soybean is before soaking, and the left two soybeans are after 18 hours of soaking. After soaking, total soybeans weigh 1435 g.

Step 5

Add the soybeans into the inner pot of Instant Pot. Fill the pot with filtered water to about ½ inch (1.2 cm) above the beans (roughly 8 cup line of the pot).

Step 6

Close the lid and set HIGH pressure for 20 minutes. Make sure the steam release handle points at “sealing” and not “venting”.

Step 7

STOVETOP OPTION: Alternatively, you can cook the beans on the stovetop. Bring to a boil over high heat, skim off the surface scum, lower to a simmer, and cook for about 3-4 hours, uncovered, until the beans are soft. Add water as needed during simmering. You want to keep the soybeans submerged in just enough water.

Step 8

Meanwhile, in a large bowl (you will add mashed soybeans in this bowl, so use your largest bowl/pot/container/dish), combine the rice koji and salt with your hands.

Step 9

Also, put some alcohol (shochu, vodka, soju, sake, etc) on a clean cloth and wipe inside the jar you will put miso in.

Step 10

Once the pressure cooking is finished, release the pressure naturally. It will take about 30 minutes till pressure comes down completely and you can open the lid.

Step 11

Test if the beans are done, by pressing a bean between a pinky and thumb. If it is mashed nicely, it’s ready. Drain the soybeans over a bowl to capture the cooking liquid. NOTE: When you are mashing the beans, you may need some cooking liquid, so save about 1 cup just in case. Ideally, it’s best not to use the cooking liquid at all (for this particular recipe, which is designed to make miso without adding cooking liquid). Water in the miso has a higher risk of potentially causing mold growth in the miso.

Step 12

While the soybeans are still hot, transfer some of the soybeans back to the Instant Pot inner pot and mash them with a potato masher (pestle or bottle, etc). Do this process in batches so it’s easier to mash nicely.

Step 13

If you have a food processor, process some soybeans until they are in paste form. Do this process in batches so it’s easier to process.

Step 14

ONLY if the soybeans look really dry, add a small amount of cooking liquid. As I mentioned earlier, it’s best if you don’t add liquid according to this recipe, but I used a little bit. Scoop out the paste and continue with the next batch.

Step 15

Mashed soybeans must be warm/room temperature (NEVER hot) before combining them with the koji because hot soybeans can kill koji mold. Mashing takes time unless you make a small batch, so you don’t need to worry about the soybeans being hot in this recipe.

Step 16

Add the warm (not hot!) mashed soybeans into the bowl with the koji and salt mixture.

Step 17

Knead well to distribute the rice koji and salt with mashed soybeans. Take time to do this process until it’s mixed well. Add a small amount of the reserved cooking liquid, if necessary.

Step 18

Using your hands, form tennis ball-sized balls with mashed soybeans.

Step 19

Put each ball into the container and mash it with your fist and knuckle to ensure that all air pockets have been eliminated. Do one layer at a time, and make sure to press down tightly. If you have a glass jar, you can see if you miss any pockets by looking from the side of the jar.

Step 20

Repeat this process until all the balls are pressed tightly in the jar. Pat down the surface with the flat of your palm or knuckle to smooth out. Make sure you have a space left for the weight on top of the miso. If your jar/container is too small, use another container. Clean the inside surface walls of the container with a shochu-soaked cloth/paper towel to deter mold.

Step 21

Sprinkle ½ Tbsp of sea salt on top of the surface.

Step 22

Place a plastic wrap on top of the surface and make sure to cover nicely. I use my adjustable drop lid (otoshibuta) to hold down the plastic wrap while I work on covering the edges and remove it when I was done.

Step 23

Put heavy objects (or rocks) on top of the miso. I put 1 kg (2.2 lb) of table salt (cheaper than the sea salt) in a plastic bag and put it on top.

Step 24

Write down the date on masking tape and put it on a jar. Place the miso in a dark and cool place for at least 3 months (I put in a storage underneath the stairs). You can also use a dark pillowcase and try to find a darker spot in the house.

Step 25

Stir the miso from the bottom up to avoid mold forming. When checking the miso, do so quickly to avoid exposure to air. If you see any mold on the surface, carefully scrape it off. Clean the inside surface walls of the container with a shochu-soaked cloth to deter mold. Smooth the surface, place a new plastic wrap on top, and put the weight back on top. Place the container back in a dark and cool place for another 3 months.

Step 26

During summer months, the fermentation will be faster but the chances of getting mold are higher. Stir the miso from the bottom up every 2-3 weeks and check your jar regularly and remove any mold appearing on the surface. Even if a layer of mold covers the entire surface, the miso below should be fine. Just scrape off the surface to a sufficient depth where only mold-free miso can be seen. Clean the inside surface walls of the container with a shochu-soaked cloth to deter mold. Smooth the surface, place a new plastic wrap on top, and put the weight back on top. Place the container back in a dark and cool place.

Step 27

Because San Francisco is always a cool climate and does not get hot, I waited for about a year to mature my miso to be red miso. Remove the weights once the miso is done.

Step 28

Divide the miso into smaller containers so they will fit in your refrigerator. Store it in the refrigerator to prevent over-fermenting. Now you can enjoy your own miso paste made with patience, love, and perseverance.