3) Mix the koji and salt (Salted Koji / “Shio-kiri Koji”)

In a bowl, combine rice koji + salt (180 g) and mix well.
If the koji is clumped, rub it gently with your hands as you mix to break it up.

4) Mash the soybeans and let them cool

Drain the soybeans and mash them while they're still warm.
Mash to your preferred texture:

Smooth: use a food processor

Chunky: mash by hand/foot, or use a masher

Important: Let it cool—if it's too hot, the koji can weaken.

Temperature guide: cool enough that it doesn't feel “too hot!” to the touch (below about 40℃).

5) Combine the soybeans and salted koji

Add the salted koji to the mashed soybeans and mix thoroughly.
If it doesn't come together well, add the saved soybean cooking liquid little by little.

Texture guide:
You should be able to make firm miso balls (packed tightly), with few cracks.
If it's too soft, mold is more likely, so don't add too much liquid.

6) Pack into the container (Remove air pockets)

Wash the container well in advance, and disinfect with alcohol if possible.
Form the miso into balls and toss them firmly into the container as you pack.
→ This helps remove air pockets and prevents mold.
Flatten the surface and wipe the rim clean.

7) Sprinkle the finishing salt (20g)

Sprinkle the reserved 20g of salt thinly over the entire surface (to help prevent mold).

8) Start fermentation with plastic wrap + weight

Press plastic wrap directly onto the miso surface (so no air gets in).
Place a drop lid (or another layer of plastic wrap) on top.
Add a weight (about 1–2 kg, as a guideline).

☆ Fermentation (Storage Place & Time) ☆

Place: somewhere cool and out of direct sunlight
Temperature guide: around 15–25℃
Time:

6 months: a gentle, mild flavor

10–12 months: deeper, richer flavor

You can mix the top and bottom once during fermentation (“turning the miso”) if you like, but it's not required.

☆ Q＆A ☆

Q. A white layer appeared… is it mold?
A. A thin white layer (such as surface yeast) may appear.
In many cases, it's fine if you simply remove the affected part with a clean spoon.

Be careful (when to discard):

A strong unpleasant odor (rotten smell)

Red/blue/black mold spreading deeply

Strange taste or strong irritation
→ If any of these occur, discard it for safety.

☆ When It's Ready to Use ☆

It's ready when it smells like miso and the color has turned slightly brown.
For longer storage, always use a clean, dry spoon when taking miso out.