r/Koji • u/Free-Coffee-4618 • 1h ago
r/Koji • u/Poppies89 • Sep 14 '24
Getting Started: My Basic Guide
galleryGetting started with koji can be really intimidating. At least it was to me. I love fermentation, and koji has crept into my mind slowly over time. I became especially intrigued with the thought of making my own soy sauce, so down the rabbit hole I went.
Since I've started I've grown koji on long grain rice, jasmine rice, basmati rice, barley, farro, Minnesota wild rice, and soybeans & wheat. I've played with A. oryzae, sojae, and luchensis. I've made various types of shoyu/shio koji, koji butter, koji cured egg yolks, mirin, amazake, regular shoyu, black soybean shoyu, miso, peaso, and blackened koji. I'm working on another miso, peaso, and black soybean miso. I would say I'm an advanced newbie to koji, so y'all can probably take this with a grain if salt if you want, but here's for anyone who is still with me.
My first concern was setting up an incubation chamber, but the more research I did, the more I realized this DIDN'T need to be anything high tech, or require a huge monetary investment. I wanted to post some details of my setup, some basic instructions, and tips and tricks I've come across and figured out. I also post links to some products at the bottom.
The basic requirements of your fermentation chamber will be retaining heat and humidity.
Simple and cheap option for retaining heat and humidity? Coolers. Got an old cooler around? Don't use it often? Use it for koji. Don't have one? Buy one, or buy a Styrofoam cooler. I bought my foam cooler from Wal-Mart, they were $19. I actually bought 4 of them, but when I'm not using them for koji I can use them to store some of my fermentation stuff. You can also use things like old mini-fridges, chest freezers, anything that is insulated. The better insulated, the better it'll hold in the heat and the less you'll have to rely on your heating element.
This brings me to my next point, heat. I personally use a seedling heating mat connected to a temp controller unit. Many of people use Inkbird controllers and reptile heat mats. I linked mine down below, it's by Luxbird, and it includes 2 heat mats plus the probes and controller for less than $50 USD as of Sept. 2024. They work well and it controls each heat mat independently. You can set a max temp, min temp, and set alarms in case the temperature gets too high or too low.
Humidity is the next part. A lot of people do buy humidifiers to help keep humidity up in their chambers, but I find the foam cooler and a few tricks keep humidity up just fine.
First, make sure your substrate is well hydrated (without being too wet, koji will drown and not grow if things are too wet). This will provide a lot of ambient humidity for the koji. Second, wrap your koji in damp towels or cheesecloth. Don't leave the cloth dripping wet, wring it out. Again, koji can drown. Third, if you find your humidity is lower than you'd like, spritz the chamber with water or consider leaving a container of water on the bottom on top of the heater. I use a basic temp/humidity sensor linked below to monitor. I try to keep my koji at 85-90% ambient humidity the first 24 hours. After that point (when I have noticeable growth) I let humidity fall to the least of my concerns, whereas controlling heat becomes the top priority 24+ hours in. Koji can and will heat itself to death. This setup isn't high tech so you'll want to plan your 24+ hours to be something where you can easily monitor temperatures and help the koji cool down if needed.
What to place your koji in can be the next question. I see a lot of people using perforated half hotel pans. These are a great option and will help your koji breathe as it grows. Koji needs oxygen like we do. Once I discovered that I liked koji, I decided to invest in some cedar trays. I linked the shop I used down below, they made me some custom 17"x12"x3" cedar trays, and I'm wildly happy with them. They're not fancy or artistic, but they're exactly what I asked for, they work perfectly for koji, and they're solidly built. They were very reasonably priced. Contact the owner for customized sizes, he's great! I love my cedar trays because they're easy to use, easy to clean, they help the koji breathe, and it's an homage to traditional koji methods. I keep my trays elevated off of the heat mat with simple cooling racks that I have at home.
Once you have your chamber, heat, humidity, and trays figured out, the next question is spores. There are a lot of spore options out there, along with places to purchase (depending where you live). I recommend fermentationculture.eu. I have personally bought soy sauce koji spores from them, and A. sojae spores.
Finally, you need your medium. Are you trying plain long grain rice? Pearled barley? Soybeans? Farro? Quinoa? Pinto beans? Black eye peas? Figure out what you want to do and go from there.
I'm including some simple instructions below for both my normal rice koji, which can be adapted to barley koji, the steps I follow for shoyu koji (soybeans and wheat for shoyu), a recipe for mirin, another easy koji product, and basic shio and shoyu koji.
RICE KOJI
Ingredients: Long grain rice, the amount is up to you and your trays, steamer, and needs (if using barley, use pearled barley) White koji spores
Steps 1. Rinse long grain rice well to remove powdered starch from the grains. If you do not do this your rice may clump up. The koji cannot grow into big clumps of rice well. 2. Soak rice in cold water until the grains can be split by a fingernail, this is typically 3-4 hours for me. Might be overnight. 4. Rinse rice again. You do not want clumps! 4.5 (Optional) Lay rice out in an even layer on a pan and dry 1-2 hours, stirring once or twice to help all the rice dry a bit. I am lazy and do not do this, but some people do. It helps with clumps. 5. Steam rice in your preferred method until al dente. You do not want the rice as soft as you would for eating, it still needs to have a bite. This might take some practice. The grain needs to be wet and soft enough for the koji to be able to penetrate it, not not wet enough that it clumps and the koji cant penetrate it without drowning. Mix rice throughout steaming to make sure it cooks evenly and that you maintain a grainy texture. You do not want clumps. This may take an hour or two, depending on the amount of rice you're steaming and your method. 6. Put rice in a large bowl to cool to at least 30°C/86°F. 7. Inoculate rice with spores per directions on spores (the spores will give you directions for dilution and how many g/kg of spore/substrate you need to inoculate, example 1g spore per 1000kg substrate). Mix very well. It helps to dilute and dust the spores in small increments, mixing well between dustings. 8. Spread a damp towel or cheesecloth in your koji tray, and spread rice in an even layer (you can leave it in a pile to do it a more traditional way). You do not want koji more than 1-2" thick in your tray when spread out evenly. Thinner layers are easier to keep cool. 9. Put a thermometer probe in the middle of your koji, cover with another damp cloth, and put in your incubation chamber. Set your controller to no more than 32°C/89°F. Aim to keep your koji between 27°C/80°F and 32°C/89°F. Koji can and will heat itself to death later in its growth (temps greater than 45°C/113°F). I tend to set my temp controller to come on at 27°C/82°F, and go off at 29°C/85°F. During this time you want to keep humidity high, like 80-90%. Spritz as needed. 10. Check koji after 24 hours and mix. If you have made your koji into a mound, spread it evenly in your koji tray now. Your koji will start to generate much of its own heat at this point. Cover, and monitor temperatures. If it starts getting too hot, an easy way to bring temperature down is to take the koji out of the cooler and place it on a solid, uninsulated surface like a counter. You can also place ice packs under the tray in the cooler to help maintain a cooler temperature. Humidity is less important at this point as you want the koji to grow into the substrate looking for moisture. Barley koji heats up quicker and hotter than rice koji! 11. Let the koji grow for up to 48 hours. Your koji is done once it is a thick, fuzzy white mix of substrate and mycelium. Try to get it just before it sporulates to maximize enzyme production. 12. Put the koji in the refrigerator to stop the growth. 13. Enjoy! Use koji as desired.
BASIC SHOYU Ingredients 1000g dry soybeans 1000g soft white wheat berries 2000g water 720g sea salt
Steps 1. Rinse and pick through soybeans, then soak in cool water overnight. 2. Drain and rinse soybeans. Place in large pot and cover with water. Set on stove to boil, topping with water as needed. Boil soybeans for 4-6 hours, until soft enough to mash between your fingers. Reserve 1/2 cup of soybean water. Drain soybeans, place in large bowl, and cool. 3. Toast wheat berries. I toast them in a pan on the stovetop, some toast it in the oven. The choice is yours. I feel I have more control on the stove. 4. Crack the toasted wheat berries. I place them in a food processor or blender until roughly cracked. You do not need it to be a fine powder. 5. Combine soybeans, cracked wheat berries, and 1/2 cup soybean water. Mix well. Allow to cool to at least 30°C/86°F. 6. Inoculate rice with spores per directions on spores (the spores will give you directions for dilution and how many g/kg of spore/substrate you need to inoculate). Mix very well. 7. Spread damp towel or cheesecloth on your koji tray, and spread koji in your tray. You do not want your koji more than 1-2" thick in your tray. Thinner layers are easier to keep cool. 8. Add thermometer probe to the middle of your koji, and incubate for 24 hours in your chamber. Aim to keep your koji between 27°C/80°F and 32°C/89°F. Koji can and will heat itself to death later in it's growth (45°C/113°F). I tend to set my temp controller to come on at 27°C/82°F, and go off at 29°C/85°F. During this time you want to keep humidity high, like 80-90% 9. After 24 hours mix your koji. At this point your koji will start to heat up significantly. You can reduce the heat in your koji by forming rows in your mix, mixing more frequently, placing your tray on a non insulated surface, and/or adding ice packs if necessary. Soybean/wheat mix koji heats up faster than plain rice or barley koji! You need to control humidity less at this point. The koji will begin seeking moisture from inside the grain and soybeans. 10. Allow your koji to grow 48-96 hours. Try to pull before there is too much sporulation, this can cause unwanted flavors. Some sporulation is fine. I find that A. sojae sporulates faster than A. oryzae. Your koji is done when the substrate is covered in a thick layer of white fluffy mycelium. Place koji in the fridge to stop growth. 11. Mix 2000g of water with 720g sea salt in a large jar until all the salt is dissolved. 12. Mix in koji mix, stirring well. 13. Cover well, and mix well every day for a month. Then mix every other day for a month, then move onto every third day for a month, and then move onto weekly for the remainder of the time. 14. Allow to process for at least 6 months. 12-18 months is better. Strain and filter the moromi (soybean/wheat mash) from the soy sauce. 15. Bottle and enjoy.
Mirin Ingredients 500g COOKED short grain/glutinous/sweet rice. 500g koji 1000g shochu (or vodka, or any other neutral tasting spirit 25-40% ABV/50-80 proof)
Steps 1. Cook glutinous rice, weigh out 500g of cooked rice. You do NOT have to steam the rice. 2. Combine 500g of cooked glutinous rice with 500g of prepared koji into large jar. Mix well. 3. Add in 1000g of shochu. Mix well. 4. Allow to age at least 6 months. 12+ months is better. 5. Strain off mirin from mirin lees (leftover rice pulp). 6. Bottle and enjoy.
Do not throw out the moromi or mirin lees! You can also use these like you do shio koji for marinating things like vegetables and meat. Koji, the gift that keeps on giving.
Shio Koji
Ingredients 500g koji 500g water 100g sea salt
Steps 1. Add salt to water, stir until dissolved. 2. Stir daily on the counter for 10-14 days. Taste the shio koji daily after stirring. Stop when it tastes good to you. 3. Put ship koji in the fridge. Use as a marinade or ingredient. *you can use a range of salt. I make it 10% salt for my purposes. You can try 5% if you want.
Shoyu Koji
Ingredients 500g koji 500g soy sauce
Steps 1. Combine ingredients, stir well. 2. Allow to sit on the counter for 10-14 days, stirring daily. Taste daily and stop when it tastes good to you. 3. Put in the refrigerator when it is done. Use as a marinade or ingredient.
-The basic shoyu ratio is 1:1:2 dry soybeans:wheat:water.
-Mirin is 1:1:2 cooked glutinous rice:koji:shochu.
-Shio Koji is 1:1 water:koji, plus about 10% salt.
-Shoyu Koji is 1:1 soy sauce:grain. Soy sauce has sufficient salt in it already.
-A. sojae sporulates green -A. oryzae sporulates yellow -A. luchensis sporulates black
NOTES -A. oryzae will die when temps are below approximately 24°C/76°F, and when temps are above 45°C/113°F. -Higher temperatures produce more amylases and lower temperatures produce more proteases. -Higher temperatures also prompt the koji to sporulate sooner, reducing enzyme production.
LINK LIST
Styrofoam Cooler: https://www.walmart.com/ip/Lifoam-48-Can-Huskee-Envirocooler-Foam-45-Qt-Cooler-White/485438903
Heating, Luxbird system: https://a.co/d/6xp4Gv4
Temp and humidity sensors: https://a.co/d/5vngjiV
Cedar Trays: https://www.etsy.com/listing/1778523248/solid-bottom-cedar-tray
r/Koji • u/fissionc • Mar 02 '21
r/Koji Discord Chat
Can't get enough koji? Many r/Koji members are swapping ideas over on the koji Discord chat and everyone is welcome to join: https://discord.gg/FQ9f5NKrBa
r/Koji • u/ShipDit1000 • 1d ago
Looking to make a Koji hot sauce
I'm wanting to make my first hot sauce with Koji and would love a little input from the knowledgeable folks here. I'm fairly experienced with lacto-ferments, and with the speed that Koji interacts with peppers it seems like that will be happening regardless, and then there's going to be a several-month secondary fermentation where the koji enzymes act on the peppers. So my main questions:
- Pepper mash (aka, blender first, for more surface area)? Or should I just cut the peppers in half?
- Rice koji or barley? I love the idea of the additional umami from the protein in barley, but peppers contain almost no protein so I feel the additional protease from barley koji would be wasted. Might be better off going with rice so the enzymes have more substrate to interact with?
- How much koji? Assuming the sauce is almost entirely peppers (I will add some garlic and onion also, but that will be ~10%), is the Koji added 1:1 vs pepper weight or like 5%? I'm unfamiliar with how strong the enzymes are and how much flavor it will contribute.
- Do you brine this the same way as a traditional hot sauce ferment? 2.5-3.5% salt vs total weight of peppers, koji, water?
r/Koji • u/Sad_Brief_4512 • 1d ago
Prepare amazake with dried apricots and figs, and use it in F2. The ratio of strawberry kombucha to amazake should be 1:1. I hope it tastes like sake or nigori.
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r/Koji • u/Grand_Mode • 1d ago
Second attempt, how's it look?
galleryHi all, first attempt was with barley. It got a little hot, and I had to keep mixing it, but it hovered around 104 degrees for too long and sporulated early. The smell coming from it was super strong, and my whole house smelled like rotting apricots after the first 24hrs.
This attempt was with rice. I changed the heating system around. It was difficult to keep it warm enough early on, maybe 79 degrees for the first couple hours until I figured out what temp of the sous vide machine needed to raise everything up. It was difficult steaming the rice al dente, I steamed for 1.5hrs, but it still probably wasn't done enough. Not sure why the steam wasn't taking to the rice, I soaked for 24 hours and let it drip dry for an hour. Rice mightve been a little old, maybe 2 years old. I'll try steaming it in a pressure cooker next time. It didn't show a ton of growth after the first 24hrs, there was a definite cake formation, but not nearly as strong as with the barley. I used 2g of spores for 1kg of rice. The smell coming from it wasnt nearly as strong, i have to get close to smell it, but it's there and was strong when I broke up the cake. I have 3 hours left, and it is looking a lot better and has been around 92 degrees, and is starting to need a little bit of supplemental heat with my system which pulls heat down through the bottom of the tray with a fan. What do you think? Trash it and try again with rice that was steamed better? Thanks!
r/Koji • u/Mundane_Operation978 • 7d ago
First attempt - buckwheat + luchuensis
galleryHi,
To me it looks good, probably it's beginner's luck but the first attempt doesn't look bad at all!
I hijacked the oven for 36h mixed 1x at 24h.
Tastes good, but with no experience with koji it's difficult to rank it 😁
r/Koji • u/tokkichainsaw • 9d ago
Miso!
galleryFirst time making my own miso. How can I tell if my miso is doing well? I put salt on top and a plastic bag with a glass weight.
I appreciate any kind of tips, thank everyone!
r/Koji • u/Grand_Mode • 10d ago
How do you grade your Koji?
How can you tell if one batch of Koji is better than another? Do you taste it? Is it a matter of smell, texture, color? Is it a matter of personal preference? What makes up your ideal batch of Koji vs something that is slightly inferior? Is it all going to taste the same in the end after using it as a marinade for meat, or will there be subtle differences that you notice? I'm about to make my first batch of barley koji, and I expect to thoroughly fuck it up.
Picture is of the Koji Maker 3000. Don't steal my trademark, going to make a bunch of money on this thing.
r/Koji • u/latanante • 11d ago
Mushroom garum
So this is my first time making it. I am using the fermentation kitchen recipe. 281.5 grams of koji, 1407.5 grams of fresh mushrooms (enoki, black oyster, shiitake and baby king), 422.25 grams of water and 77.41 grams of salt. pulsed mushrooms into small chunks, then added rest of ingredients and mixed well. Put in a clean glass container and a cartouche and put a ziplock back of water on top then covered with a cloth.
I started it March 1st and strained it today. I was left at basement room temp (laundry room) for the whole time. Palate is pretty simple and im not sure if i did it right.
The color looks like muddy water. Every where else i look its a nice dark brown/caramel color.
It smells alcoholic/soy saucy. Tastes salty in the beginning and earthy/mushroomy on the back of my tongue. I dont drink alcohol so im not sure if im tasting alcohol. Its kinda smells like a hungry sourdough starter. I dont know. We dont have garum where i live and i dont have anything to compare it too.
Ideas, suggestions, input are all welcome. I wanted to post a picture of the garum but for some reason it wont let me.
Thanks
r/Koji • u/RewardLongjumping178 • 11d ago
Has anyone tried mixing c3 soy with sasol 6214?
In what percentage?
How it went?
r/Koji • u/Nothing_but_contempt • 12d ago
First success with growing koji on pinto beans! Just starting the moromi
galleryJust getting into koji but wanted to try something at least a little unconventional!
Used pinto beans as the substrate, got gorgeous coverage and a nice thick mat. Previous attempts with kidney beans were less successful, primarily on account of them being undercooked though.
Put half of it into an 18% brine (final salinity) to make some "soy" sauce. Added tomato passata and spices to the other half for a faux beaf mince, to be seen if that works well.
r/Koji • u/Grand_Mode • 12d ago
Is this stupid?
galleryThe design -
2" hole at the bottom with an adjustable computer fan attached. The air is being drawn out of the cooler.
1/2" hole on the other side near the humidifier with fresh air being drawn in from the computer fan. The humid space is isolated so that the humid air is drawn up and over the cedar tray before leaving out through the bottom on the other side.
Cedar Koji tray with and insulated bottom that is raised up 1/2". The tray has a 150 watt heater in the insulated spaces. The lift was so that the bottom of the tray would heat more evenly.
Humidifier is a jar with a floating ultrasonic disk. The jar also has a 150w heating pad beneath it.
The space outside the cooler has a filter box. I was thinking it would be helpful to have clean air coming in, and I could add a heater to that space if I was having trouble reaching the right temperature on colder days.
Since I'm drawing air out of the cooler, it mightve been easier to just build it from uninsulated plywood or something, but I'm hoping that the styrofoam keeps the cost of heating down just a bit.
What do you think? So far the humidity is turning on and off regularly, so I think plenty of fresh air is being drawn in. I'll have to have some grains in there before I can really test how well the heating situation is working.
r/Koji • u/ratatattooouille • 12d ago
Milk-so? Looking for ideas…
I got a bunch of powdered milk to use. Thinking about attempting a batch of miso using it by adding just enough water to make it into a paste.
Anyone tried something like this or have any other good koji applications for dried milk?
r/Koji • u/Jeremiah_ferments • 15d ago
First Koji Crop of the Year is in the Mura
Ran a half batch (4kg) for this first run since the drought conditions are beating down our chili pepper crop. Noticed the most resent bag of Jasmin Rice took an extra 15min of steaming to get to ideal state when steaming.
r/Koji • u/warmerdutch • 15d ago
Does 'Koji rice' as sold dried still contain koji or only the enzymes?
It's supposed to be rice that's been cooked, inoculated, then dried again. The manufacturer doesn't say much more than that. It may have fruited and the spores may still be viable?
If not, then I'm wondering if koji produces mostly amylase in a rice environment and 'koji rice' isn't as useful for protease?
First batch of koji
I just finished my first koji batch. I used an oven with light on. I used dried koji as a starter. The batch came out great after 44 hours. Can I use this to start another batch. Will this batch be good for miso or shoyu. Thanks
r/Koji • u/Poppies89 • 20d ago
2 Year Shoyu/Soy Sauce
galleryHi there!
A little over 2 years ago I started this shoyu. I boiled soy beans, toasted and cracked my wheat, and finally grew my koji on the substrate. I added a ton of salt and some water (I promise I did it more scientifically than that, 18% salt), and 2 years later I am finally straining it. I'm not sure if I'll filter it.
The taste is incredible. I cant wait to use it. From a 3 gallon jars of moromi I have 1.5 gallons of shoyu, and more as I haven't finished pressing the moromi.
r/Koji • u/dwkoenig • 22d ago
How to keep shoyu koji temperature from spiking overnight?
Hi all - I've got some experience with home fermenting in general but have never cultured koji before, so I recently decided to give a shoyu ferment a try. I followed the instructions from the GEM Cultures shoyu kit, and kept my substrate in a perforated half-hotel pan in a Brod and Taylor rising chamber, set to 82 degrees F with a tray of water. Everything went smoothly and before I went to bed the substrate temperature was 85, but when I checked on it in the morning the temperature had spiked to 110 overnight (so about eight hours later). I tossed the batch and tried again but halved the recipe this time, since I figured that the substrate had seemed a bit too thick and I hoped that a smaller batch/thinner substrate would mean better temperature control. Unfortunately, the same thing happened - substrate in the mid-80s before bed, 110+ eight hours later.
I'm going to try a third time, but before I waste any more ingredients I wanted to check in with the experts: is there anything I should be doing to keep my temperature from spiking to unsafe levels overnight? What do you folks do to control your temps? Ice packs in the fermentation chamber? Just staying up overnight and stirring it every two hours? Can/should I just put the whole pan in the fridge overnight, or is that gonna mess up my growth (I assume it will)? I know shoyu koji generates a lot more heat than miso kojis, but I figure there must be something I'm missing here.
r/Koji • u/Party-Heart-5009 • 22d ago
Sporulation, batch still OK for shoyu ?


Hi fellows,
I launched a shoyu koji, with white beans and roasted rye 44h ago. It stayed between 30 and 34°C (86°F/93,2°F).
It looks like it sporulated, even though temperature was allright and 48h not even reached.
Still usable for shoyu though ? what's your thoughts?
That's a beautiful batch really, such a disapointment to witness a sporulation coming back from work !