Shoyu Koji vs Shio Koji in Umami, Recipe, Usage

A new type of seasoning called “Shio Koji (塩麹)” became a hot topic in Japan several years ago.

The fermented and aged pasty sauce made from just 3 ingredients, koji or malted rice, salt, and water, Shio Koji now has become a popular versatile seasoning and is used to marinate or tenderize food or enhance umami taste.

In fact, the lumpy white sauce Shio Koji can be used with a variety of foods, which include meat, fish, and vegetables, and typical usage of it includes the following.

Pork Slices Marinated in Shio Koji

  • Marinating a slice of meat or fish for a couple of hours to overnight in Shio Koji tenderizes the food and increases its umami taste thanks to the enzyme produced by aspergillus contained in Shio Koji
  • Pickle vegetables, such as sliced cucumber, in Shio Koji for several hours, and you can easily make Japanese pickles
  • Some Japanese like to dress vegetable salads with Shio Koji. They have said on the internet that Shio Koji and sesame oil make a good combination

Shoyu Koji (醤油麹)

Actually, in addition to Shio Koji, another fermented seasoning has become popular in recent years in Japan. The new type of multipurpose Japanese seasoning is called “Shoyu Koji (醤油麹)”, which is made only with 2 ingredients, malted rice, and soy sauce, with fewer ingredients than Shio Koji. However, Shoyu Koji is especially superior to Shio Koji in umami.

The Difference: Shoyu Koji vs Shio Koji in Umami

Shoyu Koji and Shio Koji

Shoyu Koji has a much more savory umami taste than Shio Koji, because the main ingredient, “Shoyu (醤油: soy sauce)” is made mainly from soybeans, which gives Shoyu Koji plenty of umami. In fact, it is said that Shoyu Koji contains more than 10 times the umami component of glutamine that Shio Koji has.


Nonetheless, it is relatively easy to prepare Shoyu Koji whose making actually takes less time than average Shio Koji recipes. As an example, based on this article on, here let me share a basic recipe for Shoyu Koji.

Shoyu Koji

Ingredient Ratio
Soy Sauce (Shoyu) 1
Malted Rice (Koji) 1
  1. Put koji in a Tupperware and add in the same amount of Shoyu or soy sauce as the malted rice
  2. Stir the mixture well once a day for feeding air and enhancing the fermentation, for about 1 week or so
  • On the second day, if the malted rice soaks up the liquid, add some soy sauce again until immersed
  • Keep the mixture at room temperature, not in the refrigerator, during about 1 week of the making process

After you make it, keep the Shoyu Koji paste in the fridge and you can enjoy it for up to three months.

How to Use Shoyu Koji

Cold Tofu with Shoyu KojiImage:

As I mentioned above, both Shoyu Koji and Shio Koji are versatile seasonings. But the salt-based fermented seasoning, Shio Koji is mainly used as a marinade, while the soy-sauce-based seasoning, Shoyu Koji can be widely used instead of soy sauce.


  • Put Shoyu Koji on grilled fish as a condiment, instead of soy sauce
  • Season cold tofu or natto with the fermented soy sauce
  • Make a dip with Shoyu Koji. For example, the brown paste pairs well with mayonnaise
  • Make a dressing by combining Shoyu Koji with other seasonings like vinegar, olive oil, and honey


Hi, I'm Tomo, a Japanese blogger living in Niigata Prefecture, Japan. For the purpose of enriching your life, I would like to introduce things about Japan on this blog, especially unique Japanese products, cooking recipes, cultures, and facts and trivia.

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