Koji. What is it, how do I use it, and can I grow it myself?
When making Koji-rice, or as it is called, “Koji-Kin” you are growing mold onto steamed rice, that’s it. The mold’s name is Aspergillus oryzae, it's a kind of good mold, plus it's said to be good for you as well. Koji is white and furry when it's in peak growth, and the heart of sake. Without Koji you couldn’t get the parallel fermentation you need to turn the starch into sugars and then into alcohol. You can buy it from Amazon, or you can grow it yourself. I can definitely advise that buying it is way easier than making it. I have been trying to grow my own Koji for the last 8 months and it has been one failure after another, but I am not giving up hope that one day I will be able to produce my own.
Supposedly it takes 24-48 hours to grow nice and fluffy. I have been using “Sake Homebrew Starter” from Vision Brewing in my growing practice when not brewing sake. This has been a trial and error type of event. I use premade koji I buy online for my sake, (for now). I even built my own humidifying mold growing box out of a Styrofoam cooler, seed heating mat with temp control and temperature probe. Still, I don't get the coverage of mold on my rice one would think after buying it from online. I am either doing something wrong, or the directions are wrong on the back of the package, (Which wouldn’t be the first time that has happened while learning how to brew sake).
Aspergillus oryzae spores are sprinkled onto a designated amount of steamed rice that is soaked prior to steaming. The infected rice is placed in a clean, humid area and allowed to grow. After a day or two you have all the Koji-rice you need at half the cost, unless you keep messing up like me. After growing it you can take it and dry it out to make it last up to a year outside of the fridge, or don't and then use it within a month if you keep it in the fridge. By cooling it down you stop the growing process. If you want to make more spores let it grow until it turns a greenish color and then sift it for the spores. A warning though while sifting, spores tend to fly up so have a mask over your mouth and nose and do not have children around when you do this because this could activate unknown allergies or asthma in them.
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