Miso Salt Ratio Calculator
Weigh your soybeans, pick a miso style, and get the koji and salt to knead in - plus the finished paste weight and how long to age it.
Results
- Koji to mix in
- 1,000 g
- Total paste weight
- 2,128 g
- Fermentation time
- 2.5 months
Dust the packed surface with a little extra salt to deter mold, then weigh the paste down so it stays under its own brine.
How the miso ratio works
Koji is dosed as a percentage of the bean weight, by style: white shiro uses equal parts koji and beans, red aka about 60% and barley mugi about 80%. Salt is specified as a percentage of the finished paste, and the paste includes the salt itself, so the kernel solves salt = (beans + koji) x salt% / (100 - salt%). More koji and less salt ferments faster and sweeter; less koji and more salt takes longer but keeps sharper, saltier miso.
If you are growing your own culture, the koji incubation calculator plans the rice batch behind this miso, and the salt weight calculator converts any salt weight into tablespoon measures for the brand you use.
Frequently asked questions
What is koji and where do I get it?
Koji is cooked rice (or barley) inoculated with Aspergillus oryzae, the mold that makes the enzymes breaking beans into amino acids and sugars. Buy it fresh from Japanese or Korean groceries or online koji makers, or grow your own with spores - the koji incubation calculator plans that batch.
Can I change the koji and salt percentages?
Within limits: koji from about 50% to 150% of the bean weight and salt from about 5% to 12% of the paste all produce real miso. Lower salt ferments faster but spoils more easily, so do not go below roughly 5-6% for a batch that ages at room temperature for months.
Why is the salt figured against the whole paste?
Because that is how miso recipes state it: 6% salt means 6% of everything in the crock, beans and koji included. Salting against the bean weight alone would overshoot once the koji and its moisture join the batch, so the calculator solves the algebra for you.