Shio Koji (White or Brown Rice Koji)
A simple, versatile seasoning made by fermenting rice koji with salt and water. Use as a quick “pre-ferment” to unlock deep savory flavor and tenderness in vegetables, beans, tofu, and grains.
Takes 10 days 15 minutes
Serves 16
Ingredients
Use one of the following (same method for both):
Brown rice version:
- Brown rice koji – 250 g 1 ¼ cups
- Fine sea salt – 25 g 2 tbsp
- Water cooled, boiled – 250 ml (1 cup)
White rice version:
- White rice koji – 250 g 1 ¼ cups
- Fine sea salt – 25 g 2 tbsp
- Water cooled, boiled – 250 ml (1 cup)
Instructions
Sanitize your kit
- Scald a 1-litre (4 cup) jar and a spoon with boiling water, then let them air-dry. This reduces contamination before adding the ingredients.
Dissolve the salt
- In a jug, whisk 25 g (2 tbsp) fine sea salt into 250 ml (1 cup) cooled, boiled water until fully dissolved.
Combine and mix (chunky or smooth)
- Add 250 g (1 ¼ cups) rice koji (brown or white) to the jar and pour in the salted water.
Rustic texture: Stir thoroughly so all grains are wet.
- Ultra-smooth, no-grit marinades: Blend all ~525 g (2 ½ cups) contents briefly to a coarse paste, then return to the jar.
Set the right consistency
- Ensure the solids are just submerged (a thin 3–5 mm layer of liquid above the koji). If needed, add a splash of more cooled, boiled water to cover the grains.
Ferment at room temperature
- Cover the jar loosely (or use a clip-top that self-vents). Leave at 20–24°C (68–75°F) for 5–10 days, stirring once daily to re-submerge any floating grains and aerate lightly.
Taste for readiness
- From day 5, taste a little: you’re aiming for sweet–salty, fruity/chestnut aromas, and a mellow savory finish.
- White rice koji usually finishes in 5–7 days.
- Brown rice koji can take 7–10 days and tastes slightly nuttier.
Finish and store
- When the flavor is right, blend again (optional) for a silky texture. Transfer back to the jar, close the lid, and refrigerate. Your ~520 g (2 ½ cups) shio koji keeps 4–6 weeks chilled (often longer). Stir before use; separation is normal.
How to Use
- Marinades / pre-ferments:
- Use 6–10% of food weight (e.g., 60–100 g shio koji per 1 kg vegetables/beans/tofu). Rest 12–24 hours in the fridge, then cook.
- Seasoning:
- Whisk 1–2 tsp (5–10 g) into dressings, sauces, or vegan mayo.
- Glaze:
- Brush a thin layer on vegetables before roasting to enhance browning.
Notes
- The 10% salt here is by koji weight: 250 g koji → 25 g salt.
- Keep surfaces wet to discourage mold; discard if you see fuzzy colored growth or sour/off smells.
- Brown-rice shio koji tends to be sweeter and nuttier; white-rice shio koji is cleaner and slightly quicker.