RECIPE: Shio Koji (Salted Rice Malt) Tomato Pasta

  • 3 min read
RECIPE: Shio Koji (Salted Rice Malt) Tomato Pasta


If you have never cooked with shio koji before, this simple pasta recipe is a tasty way to get acquainted with using this unique ingredient! 

Shio is the Japanese word for “salt”, while koji is a specific strain of mold that is used to ferment cooked rice. While it might sound odd to purposely cook with mold, koji has been a staple in Japanese cuisine for centuries. In fact, it is the foundation of several popular condiments including miso, soy sauce, rice vinegar, and sake. Rich in protease and enzymes, koji breaks down ingredients to highlight their natural flavors.

Shio koji is extremely versatile and can be used as a salt substitute, pickling agent, base for dressings/sauces, and marinade for meat and fish. In this recipe, shio koji is used in place of salt to enhance the sweetness of the tomatoes. 

We make a basic red sauce by cooking down minced garlic and chopped tomatoes, which is then flavored with shio koji and mirin (rice wine). Shio koji adds saltiness and umami, while mirin adds sweetness. Taste as you cook and add more or less of both condiments according to preference! If your tomatoes are not as ripe, try adding more mirin to sweeten the sauce. 

This recipe is extremely versatile and serves as a good base for additional ingredients. We recommend chicken, broccoli, and asparagus, but feel free to choose any proteins or vegetables that you like! Garnish with cheese, basil, and black pepper and serve piping hot.


Servings: 3 

Prep time: 5 mins
Cooking time: 15 mins


Optional toppings

  • Cheese
  • Basil
  • Boiled or grilled chicken


  1. Add the olive oil and minced garlic to a pan on high heat. Once the garlic becomes fragrant, add the chopped tomatoes. Lower the heat to medium. Gently stir and cover with a lid.
  2. After a couple of minutes, remove the lid and add the shio koji. Cook until the sauce becomes soupy. Lower the heat to low and thicken the sauce by stirring it periodically.
  3. Remove the skin of the tomatoes. Adjust the taste by adding mirin and shio koji as desired. Once the sauce has reduced by half, turn off the heat.
  4. Cook the spaghetti as per the directions on the package and add it to the pan. Toss the spaghetti and tomato sauce. You can also add cheese if desired.
  5. Serve on a plate. Garnish with some herbs, Parmesan cheese and black pepper. Ready to be enjoyed!



  • The toppings are endless. You can add more cheese, chicken, broccoli, asparagus or any other kind of seasonal vegetable would be perfect!


  • If you are using salt instead of the shio koji, keep in mind that salt is much saltier than shio koji so please don’t add too much salt. Starting with 2 tsp of salt would be enough.
  • If your tomatoes are not ripe, please balance out the sweetness with mirin. The riper they are, the sweeter the sauce will naturally become.
  • This tomato sauce pairs well with grilled fish or chicken. It also makes for a great pizza sauce! Make a large batch and save it for later!
Storage time
  • Can be stored it in an air-tight container in the fridge for 4 days.


Recipe courtesy of Miwa's Japanese Cooking Class

Miwa was born in Kamakura. She spent one year in Texas, US and another year in California, US during high-school and university respectively. In 2016, due to her husband, Yuki’s study abroad, she spent one year in Cambridge, UK where she came up with the original idea of Japanese Cooking Class in Shinagawa & Kamakura. She is currently teaching at the biggest cooking studio in Japan while holding a class at home.  She is the mother of two and a full-time worker. Always busy her food is not for tourists but for the taste of a Japanese mother.(See her Instagram for food pictures). If you want to know the a well-balanced, time-saving and delicious Japanese family cuisine, please join her lesson!

Qualification; Medicinal cooking.
<Best classes and workshops in Shinagawa prefecture on Tripadviser (2010/06/18)>
<Instagram: @miwajapanesecookingclass>


Introduction courtesy of Britney Budiman

Britney Budiman

Britney Budiman (@booritney) is a writer, minimalist, aspiring effective altruist, and runner-in-progress with a penchant for saying “yes.” Previously, she has worked in Cambodia at a traditional arts NGO, in Brazil as a social sciences researcher, and in San Francisco at a housing start-up. She currently lives in the countryside of Kagoshima, Japan, where she teaches English. Her favorite thing in the world is good conversation.


2 Responses

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April 25, 2022

Thank you for trying our recipe Kim! We love the variations you included as well!



April 25, 2022

I made this without the optional toppings. I only had fire roasted canned tomatoes so I used those in place of the fresh tomatoes. I also added in canned tuna. It was delicious!

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