On Just Hungry and its sister site, Just Bento , I usually stick to ingredients that are fairly easy to get anywhere, especially if you have access to a decent Japanese grocery store. But since the target audience for my monthly Japan Times articles are English speakers who live in Japan, I sometimes write about foodstuffs that you can only get in Japan.
This month’s subject is shio-kōji (塩麹), a traditional ingredient that is quite trendy in Japan right now. As I explain in the article , shio-kōji is just rice, kōji-kin fungus and salt that has been fermented or matured for about a week. (Before you get all squeamish about ‘fungus’, remember that beneficial bacteria, molds and fungi are used to make foods such as cheese and yogurt too, not to mention miso, soy sauce, and beer!) Shio-kōji is rather like a mild miso without the soy flavor - it has plenty of umami, and is salty but not overwhelmingly so.
In Japan, it’s quite easy to get ready-made shio-kōji these days. If your local supermarket doesn’t have it, try a department store food hall. Or, look on Rakuten or Amazon Japan  for mailorder sources.
This is a jar of a shio-kōji made by an old traditional miso maker. It’s pricey but delicious, with a nice balance of salt and umami.
It looks just like a rice porridge (okayu in Japan or congee in China), or even rice pudding.
So you’re not in Japan, but you want to try shio-kōji. At the moment it doesn’t seem to be available at Japanese grocery stores outside of Japan yet (as of February 2012). (I checked a at Mitsuwa in Edgewater, NJ and Nara Foods in Port Washington, NY both of which are pretty well stocked stores, and neither had it.) So the only option is to make your own.
If you can find kome-kōji, or rice-kōji, steamed rice that has already been innoculated with the kōji-kin fungus, the process is quite easy. Dried kome-kōji is very handy since it keeps indefinitely until it’s needed. This is what I use. Turning dried kome-kōji to ready-to-use shio-kōji takes a week or so. I store excess shio-kōji in the freezer, and that works out great. I brought a few bags back with me from Japan, but if I run out before I’m back there again I will probably order more from Amazon Japan or Rakuten and either have my mom send it to me or use a shipping service. (See overseas shipping services ).
You can also try doing an online search for ‘rice koji’, which turns up some mailorder sources. Usually they list ‘organic brown rice koji’, which should work fine for making shio-kōji (though the organic and brown rice bits are fairly meaningless nutrition-wise, since you use so little of it per serving). Your local Japanese grocery store may have premade, non-dried (fresh) kome-kōji available, especially around this time of year since it’s used to make amazake, a traditional Girl’s Day (March 3rd) beverage. It usually comes in tubs, and can be found in the refrigerated section.
Just follow the instructions in the Japan Times article , and in a week you’ll have a batch of shio-kōji. You’ll need to add more water if you’re using dried kome-kōji (about 1.5 times the weight of the dried kome-kōji).
If you can’t find kome-kōji or you are feeling adventurous, you can buy kōji-kin spores by mailorder and make your own kome-kōji, using the rice of your choice. This is a bit tricky but can be done. See the bottom of this article for some sources for kōji-kin spores.
I am still in the early stages of experimenting with shio-kōji, but so far I think my favorite way to use it is as a marinade for chicken or fish. Here is a piece of chicken (the thigh, boned) which was just marinated in shio-kōji by spreading both sides with a thin layer of shio-koji (a tablespoon or so total), wrapped tightly in plastic and left in the refrigerator for about 40 minutes. No other seasonings were used, though a dash of pepper wouldn’t hurt it at all. It was juicy and delicious. And look at that color! That comes from the naturally occuring sugar in the shio-kōji caramelizing.
I would really like to see shio-kōji become popular around the world, and I don’t see why it can’t be. It’s especially good for people who have trouble with wheat gluten or soy, either or both of which are in miso and soy sauce. Shio-kōji is packed with umami, but only uses rice and salt.
Mailorder sources for kōji-kin spores - all merchants here will ship the spores worldwide (though maybe not other items in their catalogs):
We are gradually recovering from the shock of the burglary , though they left such a horrendous mess behind that it’s going to take a while to clean it up. But I am feeling a bit better - we already signed up to get a security system installed, and our contractor will block up that vulnerable side door as soon as the insurance inspector comes to take a look at it. Both The Guy and I would like to thank every one of you who sent words of encouragement and sympathy - they really, really helped! A big hug to you all.