Let's make miso: a step-by-step guide to making miso at home

Jul 29, 2019

Let’s Make Miso!

Excerpted from Miso, Tempeh, Natto & Other Tasty Ferments: A Step-by-Step Guide to Fermenting Grains and Beans by Kirsten K. Shockey and Christopher Shockey. Copyright 2019 Storey Publishing. Photos by Dina Avila

Once you have purchased the koji, the rest of the process is quite simple and quick (the active part at least). When you read through these step-by-step instructions, we think you will agree. See our miso recipes below the instructions for ingredient amounts. Miso is traditionally made with soybeans and a grain koji like rice koji or barley koji, but if you are looking a modern spin on miso you can use any cooked legume such as chickpeas.

We all have different styles in the kitchen. As the conductors of this symphony of microbes and enzymes, we orchestrate the ingredients and they make the music. Some of us want to have very precise control over the ingredients, measuring them to the gram. Some of us are very comfortable with just putting it all together and letting the sound track play as it will. The beauty of miso is that the microbes will do their thing either way. This is not to say that measuring isn’t important, but rather that you have latitude to work in your comfort zone. Because measuring by volume varies greatly (based on how tightly you pack the koji, what type of salt you use, and so on), we’ve included gram and volume measurements to suit your style.

What You Need

  • Beans
  • Koji
  • Bowls, various sizes, for soaking the beans, catching the bean cooking liquid, moistening the koji, mixing the beans and koji, and so on
  • Large pot or electric pressure cooker for cooking the beans
  • Colander or strainer
  • Metal spoons
  • Scale for weighing the koji and beans
  • Salt
  • Meat grinder or potato masher (optional)
  • Seed miso
  • Crock, jar, or other fermentation vessel
  • Butter knife or chopstick
  • Muslin
  • Weights
  • Cloth or paper cover
  • String or rubber band
  • Painter’s tape
  • Permanent marker
  • Notebook and pen

1. Soak your beans for 8 to 24 hours before you will be ready to make miso.

2. After the beans have soaked, boil or steam them until they are soft. They should give way to pressure when squeezed between your thumb and ring finger.

3. Strain the beans, reserving the cooking liquid. Let the beans and their cooking liquid cool to body temperature (below 100°F/38°C), gently stirring the beans from time to time to release steam.

4. Place the koji in a bowl. If the koji is dry, add a small amount of the bean cooking liquid, a little bit at a time, to moisten. You want it to be well hydrated (each kernel moist all the way through) but not wet. Once it is the right consistency, weigh the koji.

5. Combine the koji, beans, and salt in a bowl. Mash the mixture into a chunky paste with uniform small pieces. You can use a meat grinder, potato masher, or your hands. If it gets too thick, add a little of the bean cooking liquid. Note: A doughlike consistency will give you a paste-style miso, whereas a chunky texture will give you a “country” or “cottage” miso. Which style you choose is up to you.

6. Add the seed miso and mix again until everything is evenly blended.

7. Prepare the fermentation vessel by rinsing the sides of the jar with a little of the bean liquid or boiled water. Pour out the excess and then sprinkle salt evenly over the inside of the vessel.

8. Pack the miso into the vessel, a spoonful at a time, tamping as you go to remove any air pockets. Or form the miso into small balls and toss them firmly into the vessel to minimize air pockets.

9. If needed, run a butter knife or chopstick along the sides of the vessel to remove any air pockets. Smooth the surface of the paste.

10. Cut a piece of muslin to fit perfectly across the top of the miso. Place it on top. Sprinkle about 1/2 tablespoon of salt along the edges of this cover to seal any gaps.

11. Set a weight on top of your miso to press out gases. Ideally, the weight on top will equal the weight of the miso.

12. If your vessel has a lid, place it on top. Other­wise, set a cloth or paper cover over the fermentation vessel and secure it with string or a rubber band. Label it with painter’s tape and a permanent marker (it’s easy to forget what you made after a few months). Let sit at room temperature on your countertop for the first few weeks. This will give you a chance to make sure it’s settling properly before you move it to its more permanent home.

13. After a few weeks to a month, you should see liquid forming on top. If you do not see any liquid, add more weight. Once you see the tamari, even just a little, you are in good shape and can forget about the miso for months at a time.

14. After the miso has aged for a while, you will see more liquid on top. This is the tamari, and it is very flavorful. You can strain off some for eating, but the rest should be mixed right back into the paste.

15. A long-aged miso can look a little like something that you’ve been warned against. It’s okay. Keep going; your miso will beautiful underneath. When your miso is ready, you’ll remove the layers on top that have been exposed to oxygen. You will know when you reach the good miso, because it will no longer be discolored and will look and smell as it should.

16. Finished miso can be eaten as is (at right), or you can run it through a food grinder, mill, or processor if you want a smoother paste (at left). Commercial miso is often heat-treated to halt the fermentation, which renders the magic of the enzymes nonexistent. There is no need to pasteurize your miso. Simply store it in the refrigerator, where it will be stable for years. Learn much more about fermenting grains and beans in Miso, Tehmpeh, Natto & Other Tasty Ferments.

SWEETEST AND SWEET MISO FORMULAS

DRY LEGUMES: 1 pound per about 3 quarts of finished miso
KOJI: 3 times the amount of legumes
SALT: 4.5 percent of the total weight of legumes + koji (for sweetest); 6 percent of the total weight of legumes + koji (for sweet)
TIME: Age for 2–3 weeks for sweetest, or 2 months for sweet

Example: For about 3 Quarts of Sweet Miso

  • 1 pound (450 grams) dry legumes
  • 3 pounds (1,350 grams) koji
  • 1/3 cup plus 1 tablespoon (108 grams) salt

Let’s do the math:

Sweetest: 450 (grams of legumes) + 1,350 (grams of koji) = 1,800 grams
1,800 × 0.045 = 81 grams of salt

Sweet: 450 (grams of legumes) + 1,350 (grams of koji) = 1,800 grams
1,800 × 0.06 = 108 grams of salt

MELLOW MISO FORMULA

DRY LEGUMES: 1 pound per a little over 2 quarts of finished miso
KOJI: 2 times the amount of legumes
SALT: 10 percent of the total weight of legumes + koji
TIME: Age for 6 months

Example: For about 1 1/4 Gallons of Mellow Miso

  • 2 pounds (900 grams) dry legumes
  • 4 pounds (1,800 grams) koji
  • 1 cup (270 grams) salt

Let’s do the math:
900 (grams of legumes) + 1,800 (grams of koji) = 2,700 grams
2,700 × 0.10 = 270 grams of salt

MEDIUM MISO FORMULA

DRY LEGUMES: 1 pound per about 2 quarts of finished miso
KOJI: Same amount as legumes
SALT: 12 percent of the total weight of legumes + koji
TIME: Age for 12 months

Example: For about 2 Gallons of Medium Miso

  • 4 pounds (1,800 grams) dry legumes
  • 4 pounds (1,800 grams) koji
  • 1 1/2 cups plus 1 tablespoon (432 grams) salt

Let’s do the math:
1,800 (grams of legumes) + 1,800 (grams of koji) = 3,600 grams
3,600 × 0.12 = 432 grams of salt

SALTY MISO FORMULA

DRY LEGUMES: 1 pound per about 1 3/4 quarts of finished miso
KOJI: Half the amount of legumes
SALT: 16 percent of the total weight of legumes + koji
TIME: Age for 24 months

Example: For about 2 1/2 Quarts of Salty Miso

  • 1 1/2 pounds (680 grams) legumes
  • 3/4 pound (340 grams) koji
  • 1/2 cup plus 2 scant tablespoons (122 grams) salt

Let’s do the math:
680 (grams of legumes) + 340 (grams of koji) = 1,020 grams
1,020 × 0.16 = 163 grams of salt