How to Make Shio Koji and Versatile Recipes

Have you heard of the seasoning called "shio koji"? It is a versatile Japanese condiment made simply by mixing koji, salt, and water and letting it ferment. Marinating meat or fish in it makes them surprisingly tender, and it can also be used for quick-pickling vegetables. Just adding it to dishes in place of salt brings umami and a mellow richness. This article covers everything from how to make shio koji to recipes for using it, tailored for those living in HCMC.

What Is Shio Koji: A Traditional Japanese Fermented Seasoning

Shio koji is a seasoning made by adding salt and water to rice koji and fermenting it at room temperature. The enzymes produced by koji mold (protease and amylase) break down proteins and starches, drawing out the umami and natural sweetness of ingredients.

In Japan, koji has been used since ancient times for making pickles and miso, but shio koji gained attention as a versatile home seasoning in the 2010s. Since then, it has spread to many households as a simple way to elevate cooking by using it in place of salt.

Here is a summary of shio koji's key features.

• Rich in umami: Koji enzymes produce amino acids, adding a depth of flavor that salt alone cannot achieve
• Tenderizes meat and fish: Protease breaks down proteins, turning dry chicken breast or fish into moist, juicy results
• Reduces salt intake: Because umami enhances the perception of saltiness, you can use less salt for the same perceived flavor
• Simple ingredients: Made with just three things: rice koji, salt, and water

How to Make Shio Koji: Ready in 7 to 10 Days

Ingredients

• Rice koji (dried type): 200g
• Salt: 60g (about 30% of the koji weight)
• Water: 250 to 300ml

Steps

1. Break apart the koji

Break the dried rice koji apart by hand until there are no clumps. If using fresh koji, simply crumble it apart.

2. Mix in the salt

Place the koji and salt in a bowl and mix thoroughly by rubbing with your hands. Spend 2 to 3 minutes mixing until the salt is evenly distributed over every grain of koji.

3. Add water

Transfer the mixed koji to a glass or enamel container and add water. Add enough water to just cover the koji. Avoid metal containers as the salt will cause corrosion.

4. Ferment at room temperature (7 to 10 days)

Loosely cover the container (do not seal it airtight) and place it away from direct sunlight. Stir once a day with a clean spoon. At HCMC temperatures (28 to 35 degrees C), fermentation proceeds quickly and is often complete in about 7 days. This is shorter than making it during winter in Japan.

5. How to tell when it is done

When the koji grains are soft enough to crush easily between your fingers and a sweet aroma develops, it is complete. Once the mixture has become a smooth, creamy paste, transfer it to the refrigerator. It keeps for about 3 months when refrigerated.

Tips for making it in HCMC

HCMC is warmer than Japan, so fermentation proceeds faster. Manage it as you would during summer in Japan. On days when room temperature exceeds 35 degrees C, fermentation may progress too quickly and develop sourness. In that case, place the container in an air-conditioned room or ferment in the vegetable compartment of the refrigerator (cold fermentation takes about 2 to 3 weeks).

Marinating Chicken with Shio Koji: Moist and Tender Recipe

The most popular use for shio koji is marinating chicken. Chicken breast, which tends to dry out, becomes surprisingly moist and juicy.

How to make shio koji chicken

1. Poke several holes in the chicken breast (300g) with a fork
2. Spread 2 tablespoons of shio koji evenly over the surface
3. Place in a plastic bag and marinate in the refrigerator for at least 4 hours (overnight is best)
4. Lightly wipe off excess koji and cook in a frying pan over medium to low heat

The key when cooking is not to use too much heat. The sugars in shio koji burn easily, so cook slowly over medium to low heat. Covering with a lid to steam-cook ensures the inside is fully cooked while remaining moist.

Variations

• Karaage (Japanese fried chicken): Coat shio koji-marinated chicken thigh in potato starch and deep fry for crispy outside, juicy inside karaage
• Chicken ham: Wrap overnight shio koji-marinated chicken breast in plastic wrap and poach at low temperature for silky, moist chicken ham

Grilling Fish with Shio Koji: Tips for Maximizing Umami

Using shio koji instead of salt when grilling fish adds a mellow umami that salt alone cannot provide.

How to make shio koji-marinated grilled fish

1. Spread 1 tablespoon of shio koji on salmon or mackerel fillets
2. Cover with plastic wrap and marinate in the refrigerator for 30 minutes to 2 hours
3. Lightly wipe off excess koji
4. Grill or pan-fry

Fish requires less marinating time than chicken. Even 30 minutes is effective, but 2 hours produces a deeper flavor. Marinating overnight can make it too salty, so aim for half a day at most.

As with chicken, watch for burning when cooking. Use medium heat if using a fish grill, and line the frying pan with parchment paper to prevent sticking.

Vegetables Pickled with Shio Koji: Easy Side Dishes and Meal Prep

Shio koji is also ideal for quick-pickling vegetables. Unlike nukazuke (rice bran pickles), it requires no daily maintenance. Just put the vegetables in a bag and refrigerate.

Basic shio koji quick pickles

1. Cut your preferred vegetables (cucumber, daikon, carrot, cabbage, etc.) into bite-sized pieces
2. Coat with shio koji equal to 10% of the vegetable weight (for 200g of vegetables, use just over 1 tablespoon of shio koji)
3. Place in a plastic bag, press out the air, and refrigerate for at least 2 hours

Pickling for half a day allows the flavors to fully permeate, and they taste great even the next day. They keep in the refrigerator for 3 to 4 days, making them perfect for meal prep.

Recommended vegetables and pickling times

• Cucumber: 2 hours to half a day. Best when it still retains a crunchy texture
• Daikon radish: Half a day to 1 day. Develops sweetness with a satisfying crunch
• Carrot: Half a day to 1 day. Cut into sticks for a colorful presentation
• Avocado: 30 minutes to 1 hour. Takes on a rich, cheese-like flavor
• Bell pepper: 2 hours to half a day. Easily available in Vietnam, making it a convenient option

Using Shio Koji Instead of Salt: Level Up Everyday Cooking

Shio koji can be widely used as a salt substitute in everyday cooking. Replace salt with 2 to 3 times the amount of shio koji (1 teaspoon of salt becomes about 1 tablespoon of shio koji).

Where shio koji shines

• Seasoning stir-fries: Replacing salt with shio koji adds umami for a mellower finish
• Seasoning pasta: Substituting shio koji for salt in peperoncino deepens the flavor
• Soups: Adding shio koji to consomme or vegetable soup provides richness even without dashi
• Dressings: Simply mix shio koji, olive oil, and lemon juice for a versatile dressing
• Pre-seasoning pork: Rub shio koji into thinly sliced pork and freeze. When needed, just thaw and stir-fry for perfectly seasoned meat

How to Get Koji in HCMC

To make shio koji from scratch, you first need rice koji. However, in HCMC, few stores regularly stock rice koji, and many people struggle to find it.

Where to find koji

You may find it at Japanese supermarkets or imported food stores, but stock availability is inconsistent. For a reliable option, ordering from Farmi is the most convenient. You can search and order in Japanese, with refrigerated delivery in as fast as 1 hour.

Alternatively, if making it from rice koji is too difficult, you can use store-bought shio koji (liquid type). Using a ready-made product like Hanamaruki's "Ekitai Shio Koji" lets you skip the fermentation process and use it immediately in cooking.

Fermented seasonings to order on Farmi

In addition to koji for making shio koji, you can order other fermented seasonings together on Farmi.

• Miso: Combine with shio koji to make a "koji miso sauce" that doubles the richness
• Soy sauce: A few drops on shio koji-marinated grilled dishes at the end adds a savory aroma
• Mirin: Shio koji + mirin makes a slightly sweet, versatile sauce

Frequently Asked Questions

Q1. What should I do if mold grows during fermentation? White cotton-like mold is often a type of koji mold and is usually harmless. However, if green or black mold appears, there may be contamination by unwanted bacteria. Using a clean container and clean spoon, and stirring daily, helps prevent mold growth.

Q2. How long can shio koji be stored? About 3 months when refrigerated. Over time, fermentation continues and sourness may develop, but it is still fine for cooked dishes. For longer storage, freezing is also an option.

Q3. Is there a difference between store-bought and homemade shio koji? Commercial products are often heat-treated to stop fermentation, giving them better shelf stability. Homemade shio koji retains live enzymes, so it is more effective at tenderizing meat and fish.

Q4. Does using shio koji reduce salt intake? The amount of sodium needed to achieve the same perceived saltiness is lower with shio koji. Because umami supplements the salty taste, it effectively leads to reduced salt intake. However, shio koji itself does contain salt, so be careful not to overuse it.

Summary: Level Up Your Daily Cooking with Shio Koji

Shio koji is a simple seasoning made from just three ingredients: koji, salt, and water. Yet it is an incredibly versatile all-rounder: it tenderizes meat and fish, makes quick vegetable pickles effortlessly, and adds umami to any dish when used as a salt substitute. In HCMC's warm climate, fermentation completes in just about 7 days, which may actually make it easier to prepare than in Japan.

Farmi is a convenient way to source koji and seasonings. Order in Japanese and receive delivery in as fast as 1 hour, so you can start making shio koji whenever the mood strikes.

Download the Farmi app to receive koji and seasonings in as fast as 1 hour.

Related articles

• Essential seasonings for Japanese cuisine
• Where to buy miso in Vietnam
• What is mirin? Substitutes and usage

Note: This article and some images were created with the assistance of AI (artificial intelligence) and reviewed by the editorial team before publication.