A culinary world opens up for you when you get to work with Aspergillus oryzae for the first time! Depending on the type of ingredient and the temperature at which you grew the Aspergillus oryzae, you can get all kinds of beautiful flavors during this process. For example, I grew the Aspergillus oryzae on sushi rice and it tasted like vanilla, ripe mango, pineapple pear, banana, lemon and bitter chocolate. I shaped that rice into cubes and made it through the dark chocolate really special! This is wy Aspergillus oryzae is the secret of Koji-kin


Aspergillus oryzae the secret of Koji

Buy aspergillus oryzae
For most recipes I used the Aspergillus oryzae( koji-kin). This is one of the fungi that is currently the easiest to buy and that you can also grow yourself.  Besides the Aspergillus oryzae there are many other variants of this fungus.

Think of special Sake koji starters, Shochu koji starters, Miso koji starters, Soy sauce koji starters actually too much to mention. If you find it interesting, you can find more information about the many species out there. All these different fungi are used for the production of traditional Japanese and Chinese beverages and fermented foods.

Build a fermentation cabinet (space) for Koji

A fermentation cabinet can be used for many more things than for fermenting only Koji. The cabinet could be used for regular fermentation’s. You can ripen cheese in it, let alcohol ferment in it, tempé (Tempeh) in it. Grow mushrooms in and just keep going. The next project that is going to try is to make natto, if it worked out well then I’ll write a bit about it.

Making a fermentation cabinet (space) sounds a lot more complicated than it is. You can already make a fermentation room by making a hole in a tempex box and adding a heating element and a humidifier. However, you will need two more meters e.g. an inkbird to control the place.

Example of a fermentation space tempexbox


Otherwise, tap in some search terms on googling or on youtube and you’ll find a lot of stuff. From a hot water bath with pump to converted fridges, beverage containers, themoboxes can make it as crazy as you’d like.

Aspergillus oryzae the secret of Koji

Aspergillus oryzae you only have to buy once. If you use the fungus to make Koji you can choose to go beyond the white mold that sits on the product. If you allow the fungus to grow further, you will get to the point that the white fungus is slowly starting to turn brown-green. This is the moment when the fungus itself begins to form spores. The Koji now smells like fresh meat (tastes like dried raisins). If you were to go through it with your hand, there would be clouds of tracks over the Koji.

It’s not really hard to grow yourself, but it’s fun to do. So you always have traces to try some new experiments. If you want to grow the tracks myself I made a movie  for you in which you can see how I do.

Koji-kin ( Aspergillus oryzae) grow themselves

I still don’t know whether this is dangerous or not! There’s not much left in Noma’s handbook of fermentation. If you search youtube then no one is talking about the danger it would bring. If I look in Jeremy Umansky’s book (also nice on instagram) it seems to be dangerous because you could breathe the tracks! There is even a name for that disease (Aspergillosis).

If I want to have new tracks and start harvesting, I’ll wear a mask just in case. Everybody’s got it these days. It may be that over time the tracks will lose some strength. I’ve been working with the same tracks for two years now and haven’t had any problems with it. If the tracks work less, add more tracks during whatever you’re going to make.

Aspergillus oryzae preserve

The spores can be dried at a temperature of about 45-50 c and stored in an airtight pot (years). If necessary, you can also vacuum the spores and store them in the freezer.

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