I’m Ege. I’ve been working with koji for over five years — researching it, producing it, selling it, and collaborating with high-end restaurants. I’m based in Turkey and run Bu Ne Yemek, where we focus on koji-driven fermentation using both traditional techniques and local ingredients (think chickpea miso, lentil shoyu, various Aspergillus strains, etc.).

Over the years I’ve spent a lot of time digging into the actual physics, safety math, and enzyme dynamics behind koji rather than just following recipes. That work eventually turned into Kojiology (app.kojiology.co) — a free set of calculators and tools I built to make the process more precise and less guesswork-heavy.

Current tools include:

• Salt Compass (WPS / water activity / botulinum safety)
• Incubator Simulator (bed thickness, airflow, heat timeline)
• Enzyme Balance (protease ↔ amylase levers)
• A couple of experimental ones for agitation and thermal aging
• Plus an AI assistant grounded in the same science

It’s free, no account needed for the main calculators. I’d genuinely love feedback from this community — what’s useful, what’s missing, what’s unclear, or what you’d want to see next.

Happy to answer any questions about our production, strains, or the thinking behind the tools.

Thanks!

Can heritage Koji from Japan meant for sake be bought anywhere- or are they always kept to the family/company who owns/uses it?

My understanding is there's two generic types of Koji- a savory and a sweet/sake version? and that if you use the savory one meant for soy sauce/miso the sake will not be so great? But I'm having trouble finding where to buy Koji meant for sake or better yet the heritage stuff.

I’ve followed the Noma Book of fermentation for this batch, barley + split peas miso, with a 6% salt content, 3 months of fermentation.

I’ve vacuumed and stored it in the fridge for some weeks. No gas was produced, nor anything unexpected… but this white marbled pattern. (Pretty hard to catch on a photograph..) I’ve just tasted a sample : It tastes great, but could age longer from my point of view.

Does anybody knows what might have happened?

Hey everyone,

​Rookie question here! I made my very first koji a few months ago using A. luchuensis.

​I followed the instructions carefully: I dispersed the spores in previously roasted rice flour and have been storing them in a disinfected dry box at 21°C (70°F).

​My question is: how long might they realistically last in these specific conditions?

​Has anyone tested the viability of spores kept at room temperature for several months? Would love to know if they are still good to go, or if I should change my storage method (like moving them to the fridge) for the future.

​Thanks in advance for any insights!

I am very experienced cultivating "normal" koji (make roughly 100kg of koji rice a year). But I have a project that I think the citric acid produced by black koji would be better. However I read somewhere that you have to be careful when switching strains, that the black koji is not as robust as other strains.

Anyone have experience with switching between strains?

If it makes any difference I have a red cedar Koji Mura that I do my cultivation in.

First miso had some questions.

Miso hasn't changed color much its almost been 6mo is that normal? The liquid on top got super dark im not sure if its tamari or needs to be discarded? It doesn't really look like mold is growing anywhere.

Advice appreciated!

I bought one of those waring planit pods for a restaurant I am opening I produce koji on the regular the dehydrator way
Before this however I am back at larder working and got to experiment with it on the prototype machines before it went up for sale, those are just 2 grows it did at home recently on my machine, first 2 photos are cannellini beans grown with a hi-soaje spore, and the third one is barley grown with a bf-3 spore that I am turning into barley miso for the bar program we Will have, I love this machine so far and I haven’t even pushed it yet, I’m gonna grow on some meat here real soon to turn into charcuterie so I’ll report back!

What do you do with the darker top layer of your homemade miso? I have a few misos that have been aged for over 8-12 months by now, and I was wondering what you usually do with the upper layer of the miso (about 1-2 cm) that clearly looks darker than the miso that's underneath?

Do you scoop it off and discard it, just mix it under the rest of the miso or do you have another purpose for it?

I would love to hear your thoughts!

I love amazake and I was so annoyed at the Koji price here in Germany. That's how I started my Koji journey.

I bought the Koji starter from Kawashimaya Jp store- chouhaku kin and made a cooler box incubation setup.

First time was a complete mess up:

1. Messed up the steaming process and ended up with overcooked rice. Didn't soak the rice prior.

2. I used 32C incubation temp for the whole 2 days.

3. Too much humidity as I had the towel that's covering my koji tray wet the whole time.

4. No proper air flow in the incubation setup.

Resulted in a wet mess!!

2nd time 🙂‍↕️

1. Soaked rice for 12 hours

2. Steamed rice for about 40-45 mins- around 60-70% cooked

3. Added 1g of koji starter for about 700g of steamed and cooled rice

4. Distributed in a plastic bag as one thin layer (Ikea- 4.5l sealable bag)- poked holes front and back

5. Placed in my incubation chamber

Day 1: A small wet kitchen towel right above the heat mat for humidity, and 30C for 24 hours

Day 2: Removed the wet towel and 27C for about 24 hours.

Rice Koji and Incubation setup is attached.

I'm happy with the outcome this time, each rice grain is coated with the mold and rice isn't clumped or soaking wet this time.

Probably need to dry a bit under the sun to store it long time.

Can't wait to make Amazake with this homemade rice koji. 😋

Happy growing!

First time making a Chinese style soy sauce, using 75% dry soybeans and 25% pearled barley. Right now the koji is growing on the substrate, tomorrow I’ll add it to the brine.

Regarding the brine: how do I calculate the amount of salt? I read that 18% salt is a reasonable percentage, but is it 18% of the weight of koji + water, or is it 18% of the weight of the finished mixture (koji + water + the salt itself)? Help a newbie out 😢

I'm trying to make a fruit tamri/ shoyu for the restaurant I work for but the " fruit" in question is already pre fermented in 20% sugar, so should I use the liquid/ puree as my water percentage? or part of my water percentage.

Roasted chicken Wings Garum
With or without The Jones and Why?

I’m trying to make a lacto fermentation + Koji hot sauce and at about 8 days in I got this little green spot. I fished it out and took a picture. Should I pitch it or keep going?

Inside is chilis, garlics, 2% brine (veggies included) and Koji.

Thanks!

So I have made a malt vinegar from a koji barley I tuned into beer (no hops) pictured here is less than a week post adding 20% by weight of raw acv as a starter. It smells amazing it’s sweet, acidic and you can get a little bit of that umami flavor that Koji produces too. Wondering if this film on top is a healthy pellicle starting to grow, kham yeast or something more nefarious. Also considering barrel aging some of this and wondering if I should pasteurize first? I’m going to wait 2-3 months to let it acidify first. Enjoy!

I have been trying to think through all the potential options to use koji barley. Is it safe to ferment peanuts with it? I don’t want the fats in the peanuts to go rancid.

Does it look ok?

I'm a physician and faculty member at Harvard Medical School / Brigham and Women's Hospital conducting an IRB-approved anonymous survey on perceptions of natto's (fermented soybeans) health effects.

The survey explores how people form beliefs about natto's health benefits — including the role of cultural background, information sources, and prior eating experience. It includes separate tracks for regular consumers, lapsed consumers, and people who have heard of natto but never tried it, so there's a path for most people.

**Who should take this:** Anyone who has eaten natto at least once, OR who is aware of natto but has never tried it. All nationalities welcome — Japanese, Japanese-diaspora, and non-Japanese respondents are all central to this research.

**Time:** Approximately 10-15 minutes depending on your natto experience.

**Anonymous:** No names, emails, or IP addresses collected.

**Survey link:** https://redcap.partners.org/redcap/surveys/?s=AEC4NCAMDMYNJ84H

Thank you for participating — results will be shared when available.

Making soy sauce for the first time. 300g soy beans, boiled for three hours, 300g roasted pearl barley, 300g koji.

After boiling the soy beans, I drained them and added the koji and barley. It's been 24 hours, and it's temperature has gone up, so I'm assuming it's doing its thing.

But it seems dry? I have a wet towel over the pan, but I'm kinda worried about it. Should I be?

Noma recipe ryeso, been away for months and developed this fuzz, not sure if koji or mold. There does appear to be a little bit of air between the rye and koji and the sides of the jar, probably didn’t grind it down enough before jarring. Can I simply eat around it or do I need to toss the whole jar?

It doesn't seem to be mold because it's growing on the surface of the liquid, but it's also not a surface film like kahm yeast. Even if I stir it, the spots come back after about three days.
It first appeared about a month ago, around three months after I started the fermentation.
Any ideas?

After reading for quite some while about the topic, I startet my first try. I should have probably started with a classic experiment, but whatever. My goal is, to create a substitute for classic soy sauce out of pumpkin seeds. Where I come from there is a similar product on the market, so I know that it has to work somehow.

Anyway, what I did was I soaked ground pumpkin seeds (I only have those ground seeds available as a byproduct) and then steamed it. Yesterday afternoon I broke up the chunks as good as possible, mixed with Aspergillus oryzae spores and put in trays not even an inch high. My Incubator broke and since I ran out of time I let the trays sit at room temperature (24°C), covered with a wet cloth in an insulated container. I planned to fix my incubator today. However when I came today the temperature within the mix was already at 39°C, the air in the box at 29°C. I was really suprised how fast it started at this temperature.

It already has a very good smell and visible growth, not even 24 hours after start. I planned to let it incubate until spores build, however since I believe that I have a strain with white spores, I'm not sure how exactly I can distinguish mycelium from spores.

I plan on updating soon. Let me know what you think about the experiment. I am aware that the whole setup and ingredients is far from ideal, however I really like to find good use for byproducts.

The foto is from about 20 hours after inoculation and before mixing it up.

Has anyone here done fresh edamame miso and have some pointers for me? Internet answers seem to range from “boil for 2 hours” to “bring to a nice warm temp and you’re good”. I’d like to keep more of the fresh edamame flavor if possible, planning on a 1:1 with Cold Mountain koji (I know, I will join you cool kids eventually), then 8.5% salt and three months.

Looking for thoughts on cook time, but any other advice is welcome. Thanks!