A complete guide to fermented foods in Japanese cuisine for expats in Ho Chi Minh City

Fermentation is not just a preservation technique in Japanese food culture: it is the source of its depth. Miso, soy sauce, mirin, vinegar, sake, natto, tsukemono, amazake, all produced through fermentation. Much of what makes Japanese food taste distinctly Japanese comes from the glutamate, lactic acid, and enzymes in these fermented ingredients.

UNESCO recognised Washoku as an Intangible Cultural Heritage in 2013, citing in part the "delicate flavours achieved through seasonal ingredients and fermented seasonings". Keeping these foods on your table in HCM is a meaningful way to maintain a connection to Japanese food culture.

Miso: the flagship of Japanese fermented foods

Miso is a fermented paste made from soybeans, rice or barley, koji, and salt, aged for months to years. Aspergillus oryzae (koji mould) drives saccharification and enzymatic breakdown, while lactic acid bacteria and yeast produce its characteristic depth.

Golden rule: never boil miso after dissolving it. The lactic acid bacteria and enzymes in miso are heat-sensitive. Always turn off the heat first, then stir in the miso to preserve its full flavour and aroma.

Storage in HCM: After opening, refrigerate and press cling wrap directly onto the surface to prevent mould. HCM's average temperature of 28-35°C means room temperature storage will degrade quality quickly. Aim to use opened miso within 1-2 months.

Natto: fermented soybeans with a distinctly Japanese character

Natto is soybeans fermented with Bacillus subtilis var. natto, known for its distinctive stickiness and pungent aroma. It is rich in plant-based protein, vitamin K2, nattokinase enzyme, and dietary fibre.

• Classic preparation: Add the included sauce and karashi mustard, stir vigorously, and serve over hot rice
• Chilled natto: Serve with spring onion, grated ginger and shiso as a summer dish
• Variations: Mix into raw egg on rice (TKG), wrap in dried nori, or add to miso soup as an ingredient

Sourcing and storage in HCM: Frozen natto is available on the Farmi app. To thaw, transfer to the refrigerator the night before. Do not refreeze once thawed.

Tsukemono: pickled and fermented vegetables in many forms

Tsukemono is an umbrella term for vegetables preserved in salt, rice bran, koji, soy sauce, or vinegar. The degree of fermentation varies significantly depending on the method.

Managing a nukadoko (rice bran bed) in HCM: In tropical heat and humidity, commercially prepared refrigerator-type nukadoko kits are the most practical approach. Refrigerator storage with one stir per day is sufficient to maintain it. Cucumber, daikon, and carrot are all readily available at local HCM markets.

Amazake: the fermented drink known as "drinkable IV fluid"

There are two types: koji amazake (non-alcoholic), made from rice and koji, and sake lees amazake (trace alcohol). Koji enzymes break starch into glucose, creating natural sweetness. It contains B vitamins, essential amino acids, and gluconic acid, and has been called "drinkable IV fluid" since the Edo period.

• Drink straight (especially refreshing chilled)
• Mix with soy milk or dairy milk for a milder taste
• Add a small amount to dressings as a natural sweetener
• Use as a meat marinade to tenderise

Fermented condiments: soy sauce, mirin and vinegar

Soy sauce (shoyu): Made from soybeans, wheat and salt, long-fermented and aged through koji mould, lactic acid bacteria and yeast. "Hon jozo" (本醸造) on the label indicates the traditional brewing method. Refrigerate after opening.

Hon mirin: Fermented and aged from glutinous rice, rice koji, and shochu. The alcohol content (around 14%) contributes to its shelf life. "Hon mirin" and "mirin-style condiment" are produced very differently, so choose according to purpose.

Rice vinegar / junmai-su: Produced by acetic acid bacteria converting alcohol to acetic acid. Pure rice vinegar has a rich, rounded flavour and is widely used for sushi rice, dressings, and pickles.

Sourcing Japanese fermented foods conveniently in HCM through Farmi

Maintaining a consistent supply of Japanese fermented foods in HCM can be a challenge. The Farmi app lets you search and order miso, natto, soy sauce, mirin, and rice vinegar in Japanese, with delivery in as little as 1 hour. Product origin and producer information is available on each product page.

Frequently Asked Questions (FAQ)

How different are the fermentation times for miso and soy sauce? Generally, hon jozo soy sauce takes 6 months to over a year. Red miso (such as Hatcho-style) takes 2-3 years. White miso is relatively quick at around 1-2 months. Longer fermentation tends to produce deeper umami and more complex flavour.

I do not like natto. Can I get protein from other fermented foods? Miso soup, tofu, and yuba (tofu skin) are excellent plant-based protein sources. Yoghurt (lacto-fermented dairy) is also a fermented food alternative. Mix and match according to your preferences.

Is making tsukemono at home in HCM difficult? Simple salt pickles and quick-pickled vegetables are relatively easy with a refrigerator. For nukazuke, starting with a commercially prepared refrigerator-ready nukadoko kit makes it much more approachable. Cucumber and daikon are readily available at local HCM markets.

Can children drink amazake? Koji amazake is non-alcoholic and suitable for children. Sake lees amazake contains trace alcohol, so children and pregnant women should choose koji amazake. Always check the ingredient label.

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Medical disclaimer: This article is intended for general food culture information purposes only and does not constitute medical advice, diagnosis or treatment. Please consult a healthcare professional for any health-related questions.