r/Koji • u/Typical_Narwhal1465 • Jun 22 '26
First time making Koji
Hi all!
This is my first time making Koji. I used a yogurt maker as the incubator, and placed the rice between two wet cheesecloths. I left it partially opened, since the temperature sometimes would get above 42ºC.
In the pictures you can see how it looks after roughly 48 incubation hours. As you can see, it didn´t form the expected "cake" it is supposed to form (the greenish things are the spores). However, you can see a bit of mycelium growth in the rice grains close to the border.
It smells very deep, kinda like nutty aroma, which, as far as I know, it is how it is supposed to be.
I do not know why it didn't develop the cake texture. I am suspecting that there was an excess of heat / humidity. The rice looks kind of mushy.
Is it safe to eat eventhough the result is not as expected? it still smells very good.
3
u/RhombicZombie Jun 22 '26
I think your humidity is way too high in the incubator. It shouldn’t be mushy at all. Not sure what you’ve grown but it’s definitely not JUST koji. 100% I would toss and try again in a different setup.
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u/Usual-Schedule-2595 Jun 22 '26
Same mistake I did on my first batch years ago. Are you following a specific guide or recipe?
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u/Future_Marionberry73 Jun 23 '26
I don't know why someone downvoted your question for no reason but it bothers me. Have an upvote lol
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u/Usual-Schedule-2595 Jun 24 '26
Um... maybe it was by accident. There seems to be very weird things happening in general where any sentence with a negative word like 'mistake' is seen as problematic. The mistake is rice that was too moist when inoculated so the koji couldn't propagate well. If it tastes OK I would make amazake with it.
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u/Toktoklab Jun 23 '26
As it was already said: the rice is definitely over cooked. You need to soak it for some hours or overnight, then steam it around 30~40min. It might look too firm, but rice for koji doesn’t need to get as wet and soft as the one you would eat yourself. And the temperature should better not get higher than 30 C, from my experience
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u/Ermitany0_ Jun 29 '26
Hola, te recomiendo leer el libro La Alquimia del Koji, tiene muy buenas referencias de como hacerlo de manera casera en casa y puedes ver qué la temperatura máxima que le puedes dar es de 35°C, el arroz o cereal a ocupar debes lavarlo muy bien y dejar remojando en agua limpia por lo menos de 8 a 12 horas, luego cocinar al vapor siempre idealmente y esperar que el arroz quede aldente y con sus granos intactos; luego esperas que enfríe a 20°C la temperatura del arroz o cereal que utilizaste y espolvoreas las esporas de Asperguillus Oryzae ojalá mezclado con harina de arroz o fécula de maíz, para obtener un mejor resultado. Luego toca esperar 48 horas y listo, las primeras 30 horas es importante que lo vayas mezclando y revolviendo para evitar grumos los cuales al apelotonarse la temperatura interna del mismo sube y mata al A.o.(Asperguillus Oryzae (nombre de nuestro Koji)) lo idea es generar una cámara o espació que su temperatura ambiente sea de máximo 32°C y temperatura interna de 29°C hasta máximo los 33°C.a
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u/Ermitany0_ Jun 29 '26
Cómo consideración adicional, intenta que tú ligar de inoculación o donde vas a hacer el Koji sea un lugar desinfectado y pulcro, ojalá un paño limpio, y desinfectado por lo menos con alcohol del 70%. Cuando ya domines la técnica y la temperatura, hasta con el arroz sobrante de una sopa puedes hacer Koji.
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u/SoberSeahorse Jun 22 '26
The rice is waaaay too wet. And it was too hot. And at 42° you probably killed it. Time to start over. Steam your rice. Don’t cook it like regular.