Recipes

Miso, Homemade

Koji, cooked soybeans and salt, mashed together and left alone for months to years. It is one of the simplest things in this section to make and one of the longest to wait for, and it is also among the safest ferments there is — the salt makes it extremely stable. The variables are only the ratio and the time.

Fermented · Japanese · Condiment · Sauces

Miso, Homemade
Prep 2 hours plus overnight soak
Cook 6 months to 3 years
Serves Makes about 1.5 kg
Level Moderate

Koji, cooked soybeans and salt, mashed together and left alone for months to years. It is one of the simplest things in this section to make and one of the longest to wait for, and it is also among the safest ferments there is — the salt makes it extremely stable. The variables are only the ratio and the time.

Ingredients

  • 500 g dried soybeans
  • 500 g rice koji
  • 180 g salt (about 11% of the finished weight, for a long-aged miso)
  • Extra salt for the surface
  • Reserved bean cooking liquid

Directions

  1. Key ingredients

Soybeans, rice koji, salt.

  1. Soak the beans overnight, then boil or pressure-cook until a bean mashes easily under finger pressure. Undercooked beans will not incorporate. RESERVE THE COOKING LIQUID.
  2. Mash the drained beans, leaving some texture.
  3. Mix in koji and salt thoroughly, while the beans are warm but not hot — hot beans would kill the koji enzymes.
  4. Add reserved liquid to reach a firm paste, about the consistency of stiff mashed potato.
  5. Pack HARD into a crock or tub, eliminating air pockets as you go. Air pockets are where surface mold starts. Smooth the top flat.
  6. Seal the surface: a layer of salt, or plastic pressed directly onto the surface. Then weight it.
  7. Leave somewhere cool for months to years. Check occasionally. 6–12 months for a medium miso; 1–3 years for a dark one.
  8. Expect tamari to pool on top — a dark, intensely savory liquid. That is not a problem, that is a prize. Stir it back in or draw it off and use it.

Notes

PROVENANCE. Mine.

THE RATIO IS THE RECIPE. More koji and less salt gives a sweeter, faster, paler miso: shiro (white) runs about 5% salt and is ready in 2–8 weeks. Less koji and more salt gives darker, deeper and slower: aka (red) runs about 12% and takes 1–3 years. Salt is the brake, and a long-aged miso needs a lot of it. Do not reduce the salt on a batch you intend to age for years.

SURFACE MOLD HAPPENS on long ferments. White is usually fine — scrape it. Colored fuzzy mold gets scraped generously; high-salt miso is stable enough that a surface issue rarely reaches the body of the paste.

DO NOT BOIL MISO. Add it off the heat, whisked into a little warm liquid first, or you lose the aromatics and kill the live culture.

TAMARI, PROPERLY, is this liquid — the stuff that pools on aging miso. Modern commercially-sold tamari generally means wheat-free soy sauce, which is a different thing wearing the same word.

MUGI MISO uses barley koji and is earthier; hatcho uses soybean koji with no rice at all and takes 2–3 years.