Complete Guide to Japanese Fermented Seasonings: Soy Sauce, Miso, Mirin, Vinegar, Sake

1. Introduction: Fermented Seasonings Are the Backbone of Japanese Cuisine

One of the reasons Japanese cuisine was inscribed as a UNESCO Intangible Cultural Heritage is its fermentation techniques. Soy sauce, miso, mirin, vinegar, and cooking sake are all fermented seasonings created through the power of microorganisms.

For Japanese people, these are everyday seasonings, but living overseas often brings more occasions to reconsider the differences and proper uses of each one. When making Japanese food in Ho Chi Minh City, you may wonder which seasoning suits a particular dish or how to store them after opening.

This article provides a comprehensive guide to Japan's five major fermented seasonings (soy sauce, miso, mirin, vinegar, and cooking sake): their characteristics, how fermentation works, health benefits, cooking applications, and storage methods in tropical climates.

!Cover image: flat lay of five fermented seasonings arranged in ceramic bowls

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2. What Is Fermentation? A Simple Explanation

Fermentation is the process in which microorganisms (molds, yeasts, bacteria) break down food components to create new flavors and aromas. It involves the same microbial decomposition as spoilage, but when the changes are beneficial to humans, we call it fermentation.

The star player in most Japanese fermented seasonings is koji. Koji is made by cultivating the koji mold (Aspergillus oryzae) on steamed rice or soybeans. It produces large amounts of enzymes that break down starches into sugars and proteins into amino acids.

The basic steps of fermentation are as follows.

1. Making koji: Koji mold is inoculated onto steamed grains and cultivated over 2 to 3 days with controlled temperature and humidity
2. Preparation: Koji is combined with raw materials (soybeans, brine, etc.)
3. Aging: Over weeks to years, microorganisms slowly break down components, generating umami and aroma

It is this "power of koji" that produces the umami of soy sauce, the richness of miso, the sweetness of mirin, the acidity of vinegar, and the flavor of sake.

!Close-up of koji mold growing on rice grains

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3. Characteristics and Uses of the Five Major Fermented Seasonings

Soy Sauce (Shoyu)

A liquid seasoning made by fermenting soybeans and wheat with koji, then aging with brine for six months to over a year. Rich in amino acids, especially glutamic acid, the balance of umami and saltiness forms the backbone of Japanese flavor.

Main uses: Sashimi dipping sauce, seasoning for simmered dishes, adding aroma to stir-fries, tamago kake gohan (egg over rice)

Selection tips: Koikuchi (dark) soy sauce is an all-purpose type. Usukuchi (light) soy sauce is better for simmered dishes and clear soups where you want less color.

!Soy sauce fermenting in wooden barrels

Miso

A paste-like seasoning made by fermenting and aging soybeans with koji and salt. The most common type is "kome miso" (rice miso), which is divided into white miso (shorter aging, sweeter) and red miso (longer aging, deeper richness).

Main uses: Miso soup, miso-marinated dishes, miso sauce (dengaku, grilled meat), salad dressing base

Selection tips: For beginners, medium-sweet awase miso (blended miso) is recommended. It works across a wide range from miso soup to stir-fries.

Mirin

A sweet seasoning made from glutinous rice, rice koji, and shochu, saccharified and aged over about two months. Unlike sugar, mirin contains multiple sugars such as glucose and oligosaccharides, giving it an elegant, mellow sweetness. It has an alcohol content of about 14%.

Main uses: Adding gloss to teriyaki, sweetening simmered dishes, removing fishy odors, enhancing the flavor of tamagoyaki (rolled omelet)

Selection tips: Choose "hon-mirin" (authentic mirin). "Mirin-fu chomiryo" (mirin-style seasoning) contains almost no alcohol and differs in flavor and effectiveness.

Vinegar (Su)

Rice vinegar, made by fermenting rice, is the most representative type. After alcoholic fermentation, acetic acid bacteria convert the alcohol into acetic acid, producing a refreshing sourness.

Main uses: Vinegared dishes, sushi rice (sushi vinegar), nanban-zuke (fried and pickled dishes), pickles, salad dressings

Selection tips: Rice vinegar is mellow and works for Japanese cuisine in general. Grain vinegar has a sharper acidity and is also suited for cooked dishes.

Cooking Sake (Ryorishu)

A seasoning based on Japanese sake, fermented from rice and rice koji. The alcohol helps remove unpleasant odors from ingredients and draws out umami.

Main uses: Base seasoning for simmered dishes and seasoned rice, preparing meat and fish (odor removal), steamed dishes

Selection tips: Dedicated "ryorishu" (cooking sake) works fine, but using drinkable seishu (refined sake) yields a richer flavor.

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4. Health Benefits of Fermented Seasonings

Fermented seasonings offer benefits beyond flavor, with several welcome health advantages.

Probiotics and Gut Health

Miso contains lactic acid bacteria and yeast that support beneficial gut bacteria. In particular, unheated miso (made by not boiling the miso soup) allows you to consume live cultures.

Reduced Salt Intake Through Umami

Glutamic acid (an umami component) produced through fermentation provides satisfaction in dishes even with less salt. Using soy sauce and miso skillfully allows you to naturally reduce your salt intake.

Vitamin and Mineral Production

During fermentation, new nutrients such as B vitamins and amino acids are generated. A defining characteristic of fermented foods is that they become more nutritious than the raw ingredients themselves.

Improved Digestion and Absorption

Koji mold enzymes pre-break down proteins and starches, reducing the digestive burden on the body.

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5. How to Get Fermented Seasonings in Ho Chi Minh City

Some fermented seasonings are available at Japanese supermarkets in HCMC, but the selection is often limited and you may not always find the brands you want.

The Farmi app offers a wide selection of fermented seasonings imported directly from Japan. The following products can be ordered through the app.

• Mentsuyu (Product ID: 10084): An all-purpose seasoning combining dashi, soy sauce, and mirin
• Granulated dashi (Product ID: 6397): Convenient umami drawn out through the power of fermentation
• Miso (Product ID: 5085): An essential fermented seasoning for daily miso soup
• Mirin (Product ID: 5183): Adds elegant sweetness and gloss to simmered dishes and teriyaki

Same-day delivery available within HCMC. No need to carry heavy bottles and packages yourself.

!A Japanese dining table scene featuring dishes made with fermented seasonings

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6. Storage Tips for Tropical Climates

Ho Chi Minh City is hot and humid year-round. The climate differs significantly from Japan, so special attention is needed when storing fermented seasonings.

Before Opening

Avoid direct sunlight and store in the coolest place possible. In HCMC, where room temperatures often exceed 30 degrees Celsius, refrigerating even unopened products is recommended for peace of mind.

Post-Opening Storage Guide

• Soy sauce: Refrigerator, 1 to 2 months, Darkening color indicates declining flavor
• Miso: Refrigerator, 3 to 6 months, Press plastic wrap directly on the surface to prevent oxidation
• Mirin: Refrigerator, 2 to 3 months, Sugar crystallization does not affect quality
• Vinegar: Refrigerator, 6 months or more, High acidity makes it resistant to spoilage at room temperature, but refrigeration is recommended
• Cooking sake: Refrigerator, 1 to 2 months, Seal tightly as evaporating alcohol diminishes the flavor

Additional Tips for Tropical Climates

• Keep the rim of bottles clean to prevent mold growth
• Pour out only what you need into a small dish; avoid putting chopsticks or spoons directly into the bottle
• Smaller sizes that can be used up quickly are preferable to large-volume containers

!Close-up of hands dissolving miso into dashi broth

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7. Frequently Asked Questions (FAQ)

Q1. Can fermented seasonings be used past their expiration date?

Fermented foods have high preservability, so if properly stored unopened, quality does not immediately deteriorate just because the best-by date has passed slightly. However, after opening, flavor degrades more easily, so use the storage periods above as a guide. If you notice any change in color or smell, stop using the product.

Q2. Is it safe to use mirin and cooking sake in children's meals?

The alcohol evaporates almost entirely during cooking, so there is no problem using them in simmered or grilled dishes. However, for non-heated dishes such as dressed salads, boil the mirin first (to evaporate the alcohol) before use.

Q3. Any tips for combining fermented seasonings?

The basic combination is "soy sauce + mirin + sake." Mixing these three at a 1:1:1 ratio creates a base for teriyaki and simmered dishes. Add miso for a miso-simmered dish, or add vinegar for a nanban sauce variation. Start with this basic ratio and adjust from there.

Q4. Vietnam also has fermented seasonings. How do they differ from Japanese ones?

Vietnam's nuoc mam (fish sauce) is a seasoning made by salt-fermenting fish, and its type of umami differs from Japanese soy sauce. Soy sauce is primarily glutamic acid (plant-based amino acid), while nuoc mam is primarily inosinic acid (animal-based amino acid). Both have "umami" but with different flavor profiles, so using Japanese fermented seasonings is recommended for Japanese cuisine.

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Summary

Japanese fermented seasonings are ingredients filled with ancestral wisdom, harnessing the power of microorganisms like koji mold to create umami, sweetness, acidity, and depth of flavor.

• Soy sauce: The foundation of Japanese cuisine; the backbone of umami and saltiness
• Miso: The star of daily miso soup, also beneficial for gut health
• Mirin: A distinguished supporting player that adds elegant sweetness and gloss
• Vinegar: Refreshing sourness that brings flavors together
• Cooking sake: The unsung hero that removes off-odors and draws out umami

Even in Ho Chi Minh City, the Farmi app makes these fermented seasonings easily accessible. Incorporate them into your daily cooking and experience the power of fermentation.

Download the Farmi App

Japanese fermented seasonings can be easily ordered through the Farmi app. Same-day delivery within HCMC. Download the app and enjoy authentic Japanese flavors at home.

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The information in this article is current as of September 2026. Product availability and prices are subject to change. Please check the Farmi app for the latest information.