Base Miso Ratios

This is the formula reference for Making Miso. A miso is defined by three numbers: how much koji relative to legume (the higher the koji, the sweeter and faster), and the salt percentage of the total paste (which sets how long and how warm you can safely age it). Pick a style row, then scale it.

Characteristics

	What it is	Salt % (of paste)	Koji : legume	Best for
Sweet / white (shiro)	High-koji, low-salt, short-aged, pale and mellow	5-6%	~2 : 1	Dressings, light soups, quick turnaround (3-8 weeks)
Medium / yellow	Balanced everyday miso	7-9%	~1 : 1	General cooking; aged 2-6 months
Red / dark (aka)	Lower-koji, high-salt, long-aged, deep and assertive	11-13%	~1 : 1.5	Braises, glazes, long keeping (6 months-2+ years)

Note

Salt percentage and aging time move together. More salt is a stronger hurdle, so a 12% red miso ages safely for a year-plus at ambient temperature; a 5% sweet miso must finish in weeks at a controlled 18-25°C. Never push a low-salt miso into a long warm age — the salt is what holds it above the botulism line.

The formula (ratios)

Work by weight. The base paste = koji + legume; salt is calculated as a percentage of that base paste, then mixed in.

• Sweet / white: 2 parts koji : 1 part cooked legume, salted to 5-6% of the combined weight.
• Medium / yellow: 1 part koji : 1 part cooked legume, salted to 7-9%.
• Red / dark: 1 part koji : 1.5 parts cooked legume, salted to 11-13%.

Add reserved legume cooking liquid as needed to reach a firm, packable, cookie-dough texture.

Scaling table

Grams per component. The 2 : 1 sweet ratio and 5% salt are shown as the worked default; the same proportional method applies to medium and red.

Component	1 Jar (~0.75 kg)	2 Jars (~1.5 kg)	1 Crock (~3 kg)	6 Crock (~18 kg)
Koji (2 parts)	470 g	940 g	1,880 g	11,280 g
Cooked legume (1 part)	235 g	470 g	940 g	5,640 g
Base paste (koji + legume)	705 g	1,410 g	2,820 g	16,920 g
Salt @ 5% of base paste	35 g	71 g	141 g	846 g
Total paste weight	740 g	1,481 g	2,961 g	17,766 g

Tip

For red miso, rerun the same columns at 1 : 1.5 koji:legume and 12% salt. Example for 1 Crock of base paste (~2,820 g): salt @ 12% = ~338 g. The dry-salt calculator sizes the salt dose for any total weight.

Calculated values

💧 Sweet / white

Salt 5-6% of paste · koji-forward 2:1 · target finished pH ~5.0-5.5 · age 3-8 weeks at 18-25°C.

🌶️ Red / dark

Salt 11-13% of paste · 1:1.5 koji:legume · target finished pH ~4.8-5.2 · age 6 months-2+ years.

Info

Miso is salt-and-water-activity preserved, not acid-preserved — finished pH stays around 4.8-5.5, above the 4.6 botulism line. The salt percentage, not pH, is the safety number to honor. Confirm salt by weighing; pH on a calibrated meter only confirms the paste matured, not that it is “acidic enough.”

Variations

• Legume swaps: chickpea (sweeter), black bean (deeper color), or yellow split pea (peaso). Cook-soft requirement and ratios are unchanged.
• Barley koji (mugi): swap rice koji for barley koji for an earthier, rustic miso.
• Extra-sweet: push koji to 2.5-3 : 1 and hold salt at the 5% floor — but keep the age short and cool, because lower salt narrows the safe window.
• Hatcho-style: soybean koji with very little rice koji and ~12% salt for an extremely long, dark age.

See also

• Making Miso — the full build, packing, and surface-management workflow
• Growing Koji — make the koji this ratio depends on
• Salt Percentage and Preservation Hurdles
• Amino Pastes — the fast, warm-aged variant
• Dry-salt calculator