Any stage · from shopping list to ready date
Batch Plan
Every other tool here starts from what you already have. This one starts from what you want: name a ferment and a batch size, and it works backwards through the recipe, the koji cycle and the steamer to a weight of dry grain you can buy — then lays the whole thing out on a clock.
New to this? Start here
Making miso from scratch is two jobs, not one. First you grow koji — soak grain, steam it, cool it, sow mould spores on it, and keep it warm for about two days. Then you ferment with it — mix that koji with cooked beans and salt, and wait weeks or months. The plan below covers both, in order, with the quantities solved so that the koji you grow is the koji the recipe needs.
- Why the dry weight is less than the koji weight —
- Rice roughly doubles in weight through soaking and steaming, then loses about 10% of that back over the two-day cycle as the mould respires and the bed sweats. So a kilo of finished koji comes from well under a kilo of dry rice — which is exactly the sum that goes wrong when you buy by eye.
- Te-ire —
- Turning the bed by hand mid-cycle. It sheds the heat the mould is making, breaks up clumping, and strips free water off the surface. The hours below come from the reference deck's own photographs of a bed at 12, 21, 24, 34 and 46 hours.
- Mixing day —
- The one day everything has to be ready at once: koji out of the box, beans cooked and cooled, salt weighed. It is the step this plan exists to protect — see the schedule for when the beans have to go in water.
What are you making?
Kit is assumed: a 24 cm steamer basket, an 1,800 W burner, at sea level. Change any of that in Substrate Prep and the soak and steam times move with it.
2,104 g of white miso (shiro) — that is 2,000 g of ingredients plus 104 g of salt. About 180 minutes of hands-on work, spread across 2-8 weeks.
The shopping list
Dry and as-purchased weights, worked back through every stage.
- 964 gWhite rice (polished) — to grow the koji onas boughtDry weight. Becomes about 1200 g of finished koji after the 4.5 hours of prep and the 46-hour cycle.
- 322 gSoybeansas boughtDry weight. Becomes about 799 g cooked, which is what the ratio asks for.
- 104 gSaltas bought5.2% of batch weight, from the salt engine. Non-iodised.
They need about 14.2 hours from dry to cooled, so they go in water at hour 36 — while the koji is still in the box. This is the step that catches people out: start them when the koji comes out and mixing day slips by 14.2 hours, with finished koji sitting on the bench for all of it.
- The recipe's 5% does not clear the 10.7% WPS target for 8 weeks at 30°C on this substrate, so this plan uses 5.2% (104 g) instead. Salt is never lowered to match a ratio.
The ratio is an illustrative starting point transcribed from Bu Ne Yemek's guides, not a validated recipe — it can be wrong about proportion or tradition. The salt figure is not: it comes from the same engine Salt Compassuses, and the ratio's own percentage can only ever be raised by it, never lowered.
The schedule
Hours from the moment you start. Pick a start time above to see it as dates.
Day 1
h0:003 hSoak the grain for the koji
Cover 964 g of white rice (polished) with cool water and leave it 3 hours.
This is the soak that lands the guide's 30-39% loading band once steaming and cooling have had their say — not a round number.
- h3:0030 min
Drain
Drain for 30 minutes. Surface water counts — an undrained grain carries it into the steamer.
- h3:30
Steam
Steam for about 26 minutes — roughly 6 to come up to temperature and 20 holding.
Steaming does not only cook it: about 123 g of water condenses onto this batch on the way, which is why the soak above is shorter than it looks like it should be.
- h3:5635 min
Spread and cool
Spread it on a tray and cool to about 32°C — roughly 35 minutes in a 22°C room.
It passes through the 35-50°C spoilage band on the way down and spends about 13 minutes there with no spores on it yet. Moving air shortens that.
- h4:31
Inoculate
Once it is below 40°C — ideally near 32°C — break every lump apart and mix through 9.6 g of tane-koji.
10 g per kg of DRY grain, so this is sized on the 964 g you started with, not on what came out of the steamer. The full dose is competitive exclusion — koji has to reach the substrate before Bacillus does.
- h16:31
Germination — hour 12
Hold ~30 °C and high humidity. Do not open the chamber.
Spores are swelling and putting out the first germ tubes. There is no metabolic heat yet, so the chamber is doing all the work.
Day 2
h25:31First te-ire — hour 21
Break the bed up by hand, level it, and re-spread. Keep humidity up around 90%.
Hyphae are threading across the surface and the bed is starting to make its own heat. Turning it sheds that heat, breaks any clumping, and strips free surface water. Holding humidity keeps it spreading sideways, which is what sō-hazé needs.
- h28:31
Heat rises — hour 24
Probe the substrate core, not the air. Furrow the bed if the core climbs past 38 °C.
This is the metabolic heat spike. Left alone the core runs away from you, and past 45 °C the mould cooks in its own heat while Bacillus gets the substrate to itself.
- h36:2212 h
Soak the soybeans
Cover 322 g of soybeans with cool water and leave it 12 hours. These become the cooked soybeans.
This is the soak that lands the guide's 30-39% loading band once steaming and cooling have had their say — not a round number.
- h38:31
Second te-ire — hour 34
Turn and furrow again. Ease humidity down slightly so the surface firms up.
The mycelium is dense on the surface now. Everything from here is about depth, and depth only happens while the outside is the harder place to live.
Day 3
h48:2230 minDrain
Drain for 30 minutes. Surface water counts — an undrained grain carries it into the steamer.
- h48:521.1 h
Steam
Steam for about 65 minutes — roughly 5 to come up to temperature and 60 holding.
Steaming does not only cook it: about 127 g of water condenses onto this batch on the way, which is why the soak above is shorter than it looks like it should be.
- h49:5635 min
Spread and cool
Spread it on a tray and cool to about 32°C — roughly 35 minutes in a 22°C room.
It passes through the 35-50°C spoilage band on the way down and spends about 13 minutes there with no spores on it yet. Moving air shortens that.
- h50:31
Finishing — hour 46
Harvest. Spread thin and cool immediately. This strain starts throwing spores around hour 48 — do not run past it.
Enzyme content peaks and then the mould switches to reproduction. Spores taste bitter and animalic, and every hour past the deadline trades enzyme for that.
- h50:31
Mixing day
1200 g rice koji · 800 g cooked soybeans · 104 g salt
Weigh, combine and work it until the salt is evenly through — an unmixed pocket is a pocket at a lower salt percentage than the one keeping this safe.
- h50:31
Pack it down
Pack into the vessel with no air pockets, level the surface, and keep it at 20-30°C for 2-8 weeks.
Trapped oxygen is used up within about a day, which is what kills off dormant Bacillus. Air pockets are where that does not happen.
Day 17
h386:31Ready to taste
Earliest it is worth tasting. The example runs to 2-8 weeks, and longer is darker and stronger rather than wrong.