Traditional Fish Sauce Production and Uses

Fish sauce is one of the oldest condiments in human history – a fermented liquid made from just two ingredients: fish and salt. It has been a cornerstone of Southeast Asian cooking for centuries and is now gaining popularity in kitchens worldwide. From Thai curries to Vietnamese pho, fish sauce delivers a deep, savory punch known as umami that no other single ingredient can replicate. But how exactly is this pungent amber liquid made, and why does it taste so good? Let’s break it down.

What is fish sauce? 🔗

Fish sauce is a clear, amber-to-brown liquid obtained by fermenting fish with a large amount of salt over several months. The Codex Alimentarius Standard (CXS 302-2011) defines it as a translucent liquid product with a salty taste and fish flavour, produced by fermenting fish with salt in covered containers for no less than six months. The finished product is rich in free amino acids, particularly glutamic acid, which is responsible for its characteristic umami flavour.

Different countries call it by different names. In Thailand it is nam pla, in Vietnam nước mắm, in the Philippines patis, in Cambodia tuk trey, in Myanmar ngan bya yay, in Japan gyoshō, and in Korea aekjeot. Each version has its own flavour profile, fish species, and production nuances, but the core principle remains the same: fish plus salt plus time.

A brief history of fish sauce 🔗

Fish sauce is far from a modern invention. The ancient Greeks were producing a fermented fish condiment called garos as early as the 4th-3rd century BC. The Romans later adopted and popularised their own version, known as garum, which became one of the most traded condiments across the Roman Empire. Garum was made by salting fish scraps and sun-fermenting the flesh for several months before straining and bottling the liquid.

In East Asia, fish sauces fermented with soybeans and salt were documented in China over 2,300 years ago during the Zhou dynasty. Over time, the Chinese shifted toward soy-based fermented products, and fish sauce became more closely associated with Southeast Asia. Food scholars often describe a “bean-fish divide” – Southeast Asian nations like Vietnam, Thailand, and Cambodia rely primarily on fermented fish products, while Northeast Asian nations like China, Korea, and Japan lean toward fermented bean products like soy sauce.

Today, the global fish sauce market is projected to reach approximately USD 28.94 billion by 2032, growing at a compound annual growth rate of 5.1%, driven by increasing global interest in Asian cuisines and the growing popularity of umami-rich flavours.

Raw materials used in fish sauce production 🔗

The beauty of fish sauce lies in its simplicity. Traditional production requires only two core ingredients:

Fish: Small, oily species are preferred. Anchovies are the most commonly used fish worldwide, though mackerel, sardines, shrimp, and other small fish are also employed depending on the region. The fish must be fresh because freshness directly affects the final quality and aroma of the sauce. Whole fish – including the viscera (internal organs) – are typically used because the digestive enzymes in the viscera play a critical role in protein breakdown during fermentation.

Salt: Coarse sea salt is the standard choice. The salt serves two essential functions – it draws moisture out of the fish through osmosis and prevents the growth of harmful bacteria by creating an environment too hostile for spoilage organisms. The salt concentration in the final product is typically between 20% and 30%.

The traditional production process 🔗

The production of fish sauce is straightforward in principle but demands patience. Here is a step-by-step look at the traditional method:

Mixing fish with salt 🔗

Fresh fish are thoroughly mixed with salt, typically at a ratio of 3:1 (three parts fish to one part salt), though this can vary. Some Thai producers use a 5:1 ratio for larger fish, while others go as high as 1:1 for smaller batches. The salted fish are then placed into large containers – traditionally wooden barrels, earthenware jars, or concrete tanks.

Pressing and sealing 🔗

A woven bamboo mat or wooden lid is placed on top of the fish, weighted down with heavy rocks. This keeps the fish submerged, expels air pockets, and helps squeeze out the liquid as the salt draws moisture from the fish cells. The container is then sealed or covered and stored in a warm area, often outdoors under direct sunlight in tropical climates.

Fermentation 🔗

This is where the real transformation happens. During fermentation, two simultaneous processes break down the fish:

Autolysis (self-digestion): Enzymes naturally present in the fish tissues – particularly trypsin, chymotrypsin, and cathepsins from the viscera – begin hydrolysing (breaking down) the fish proteins into smaller peptides and free amino acids. This is why whole fish with intact organs are preferred.

Microbial action: Salt-tolerant (halophilic) bacteria gradually establish themselves in the high-salt environment and contribute to the development of characteristic aroma and flavour compounds. These bacteria produce organic acids, esters, and other volatile compounds that give fish sauce its distinctive smell and complex taste.

The fermentation period ranges from 6 to 18 months, depending on the region, climate, and desired quality. Some premium Vietnamese fish sauces from Phú Quốc island are fermented for over a year. During this period, the fish mass gradually liquefies, and the mixture darkens in colour.

Extraction and filtration 🔗

After sufficient fermentation, the liquid is extracted. The first liquid drawn off – without applying pressure – is the highest grade of fish sauce, often called the “first press” or nước mắm nhĩ in Vietnamese. This premium extract is clear, amber-coloured, and intensely flavourful with the highest protein (nitrogen) content.

Subsequent extractions are made by adding brine to the remaining fish mass and fermenting again for a shorter period. These later extractions yield lower-grade fish sauces that are thinner, less flavourful, and often used for cooking rather than as a finishing condiment or dipping sauce.

Bottling 🔗

The filtered liquid is bottled without the need for sterilisation. The high salt concentration – typically 25-30% – acts as a natural preservative, creating conditions where harmful bacteria cannot survive. This self-preserving property has made fish sauce incredibly shelf-stable throughout history; properly made fish sauce can last for years without refrigeration.

Grading and quality indicators 🔗

Not all fish sauces are equal. Quality is determined largely by the nitrogen content, which reflects the amount of amino acids and proteins present. The Codex standard specifies that total nitrogen content must be no less than 10 g/L, with amino acid nitrogen comprising at least 40% of that total.

In Vietnam, fish sauces carry a numerical grade expressed in degrees of nitrogen (°N per litre). A 50°N rating is considered the highest achievable standard, associated with first-press premium sauces. Higher nitrogen means more protein content, greater umami intensity, and a higher price tag. Lower-grade sauces – often second or third extractions – have lower nitrogen levels and are better suited for cooking, where the protein is less sensitive to heat.

Visual indicators of quality include clarity (the sauce should be translucent, not cloudy), colour (clear amber to light brown is ideal), and aroma (strong but clean and oceanic, not harshly fishy or unpleasant).

Regional varieties of fish sauce 🔗

Vietnamese nước mắm 🔗

Vietnam is the most renowned producer of fish sauce. The island of Phú Quốc and the coastal town of Phan Thiết are the two most famous production centres. Vietnamese nước mắm, especially from Phú Quốc, is valued for its clean, pure flavour and transparent clarity. It is primarily made from black anchovies and tends to be lighter and slightly sweeter than other varieties. Vietnam currently has hundreds of fish sauce production facilities and exports the product to more than 60 countries.

Thai nam pla 🔗

Thailand is the world’s largest exporter of fish sauce. Thai nam pla is generally lighter in colour, saltier, and slightly more pungent than its Vietnamese counterpart. Traditionally, both freshwater and saltwater fish varieties were used, with fermentation lasting at least eight months at a ratio of three parts fish to two parts salt. Thai fish sauce is used both in cooking and as a table condiment, most commonly mixed with lime juice and chopped bird’s eye chillies to make phrik nam pla – a dipping sauce served with nearly every Thai meal.

Filipino patis 🔗

Philippine patis differs from other varieties because it is a by-product of bagoong (fermented fish paste) production. The liquid rises naturally to the top of fermenting bagoong and is skimmed off rather than pressed. This means patis typically takes longer to produce. It has a heavier, more assertive, and more mineral-forward flavour. Patis is used to season dishes like sinigang (sour soup), arroz caldo (rice porridge), and adobo, and also serves as a table condiment mixed with calamansi (a local citrus fruit) and chillies.

Other notable varieties 🔗

Cambodia produces tuk trey, which tends to be thicker and stronger, often made from freshwater fish. Japan has several regional fish sauces collectively called gyoshō, including shottsuru from Akita Prefecture (made from sailfin sandfish) and ishiru from the Noto Peninsula (made from sardines or squid). In Korea, aekjeot – made from anchovies or sand lances – is an essential ingredient in kimchi production. Even Italy has its own version: colatura di alici from the Amalfi coast, fermented in chestnut barrels.

The science behind the flavour 🔗

Fish sauce delivers umami through its high concentration of free amino acids, especially glutamic acid. According to a review published in Food Research, five major amino acids contribute to the taste of fish sauce: glutamic acid, threonine, alanine, methionine, and histidine. The fermentation process also produces nucleotides like inosine monophosphate and guanosine monophosphate, which synergise with glutamic acid to amplify the umami sensation.

Extended fermentation reduces the overtly “fishy” taste and develops a nuttier, richer, more rounded flavour. Short-fermented sauces tend to have a more pronounced raw-fish character, while sauces aged for a year or more deliver complex, layered savoury notes.

Nutritional profile of fish sauce 🔗

Fish sauce is not a significant source of macronutrients, but it does offer some nutritional value. According to USDA data, one tablespoon (18 g) of fish sauce contains approximately 6 calories, less than 1 g of protein, and negligible fat. It provides about 7.5% of the daily value for magnesium, and 2-4% of the daily value for folate, niacin, vitamin B6, and vitamin B12.

The fermentation process generates all nine essential amino acids, making fish sauce a modest but complete source of these building blocks. It also contains trace amounts of potassium, calcium, and iron. Some countries, particularly in Southeast Asia, have used fish sauce as a vehicle for iron fortification to combat anaemia in populations where it is a dietary staple.

The main nutritional concern is sodium. A single tablespoon contains roughly 1,400 mg of sodium – over 60% of the recommended daily intake. However, because fish sauce is so intensely flavoured, only a small amount is typically needed per dish.

Culinary uses of fish sauce 🔗

Fish sauce is extraordinarily versatile. Its primary role is as a flavour enhancer that works behind the scenes – you don’t necessarily taste “fish,” but you notice a deeper, more satisfying savoury quality in the food. Here are the most common applications:

Dipping sauces: The most iconic use. Vietnamese nước chấm (fish sauce mixed with lime juice, sugar, garlic, chilli, and water) accompanies spring rolls, grilled meats, and noodle bowls. Thai phrik nam pla (fish sauce with chillies and lime) appears on virtually every table.

Stir-fries and curries: A splash of fish sauce during cooking adds depth and salinity. It is essential in dishes like pad Thai, Thai green curry, and Vietnamese bún bò Huế.

Marinades: Fish sauce enzymes help tenderise proteins while infusing them with umami. It is commonly used in marinades for grilled chicken, pork, and seafood across Southeast Asia.

Soups and broths: Fish sauce enriches the broth in pho, sinigang, tom yum, and many other Asian soups, often replacing or supplementing salt.

Fermented foods: In Korea, anchovy-based aekjeot is a critical ingredient in kimchi, providing both flavour and promoting proper fermentation.

Non-Asian applications: Chefs increasingly use fish sauce in Western dishes – bolognese, Caesar salad dressing, Bloody Marys, and glazes for roasted meats – to add a background layer of savoury complexity without any identifiable fish flavour.

Modern innovations in fish sauce production 🔗

While traditional methods still dominate artisanal production, modern food science has introduced several innovations. Researchers have explored using starter cultures of halophilic bacteria – such as Tetragenococcus halophilus – to improve flavour consistency and shorten the fermentation period from over a year to just a few months. A study published in the Journal of Food Science and Technology demonstrated that inoculating fish sauce mash with selected halophilic strains improved volatile compound profiles, increased glutamic acid content, and reduced biogenic amine levels in the final product.

Enzyme supplementation is another approach. Adding commercial proteases like papain, bromelain, or trypsin to the fish-salt mixture accelerates protein hydrolysis. Some researchers have successfully reduced fermentation time from 6-12 months to just 2 months using enzyme-assisted methods, while maintaining comparable flavour and nutritional quality.

Modern facilities are also adopting standardised quality control, organic certification, and sustainable sourcing practices. Smaller bottles and milder formulations are being developed for international markets where consumers may be encountering fish sauce for the first time.

Shelf life and storage 🔗

Thanks to its extremely high salt content, properly produced fish sauce has a remarkably long shelf life – potentially lasting several years without refrigeration. The salt concentration creates conditions where spoilage organisms simply cannot survive. That said, once opened, storing fish sauce in a cool, dark place (or refrigerating it) helps preserve its freshness and prevents the flavour from becoming overly salty over time. High-quality fish sauce should maintain its clear appearance and clean aroma throughout its shelf life; any cloudiness, off-odour, or mould growth indicates spoilage.

Fish sauce as a tool for waste utilisation 🔗

From an industry perspective, fish sauce production is an excellent example of fish by-product utilisation. Low-value fish species, undersized catches, and fish parts that might otherwise be discarded (viscera, heads, trimmings) can all be converted into a high-value, shelf-stable condiment. This reduces waste in the fishing industry while creating a product with significant economic value. Research has shown that fish sauce can be produced from surimi processing by-products, catfish nuggets, and herring offcuts, opening up further possibilities for waste reduction in seafood processing.

What do you think? Given that fish sauce production transforms low-value fish into a high-value product with an almost indefinite shelf life, could similar fermentation principles be applied to other food industry waste streams? And as global palates continue to embrace umami-rich flavours, how might traditional fish sauce producers balance the demand for scale with the authenticity of centuries-old fermentation methods?

References

1. https://www.fao.org/fao-who-codexalimentarius/sh-proxy/en/?lnk=1&url=https://workspace.fao.org/sites/codex/Standards/CXS+302-2011/CXS_302e.pdf
2. https://en.wikipedia.org/wiki/Fish_sauce
3. https://www.globenewswire.com/news-release/2024/10/31/2972518/0/en/Fish-Sauce-Market-Expected-to-Reach-USD-28-94-Bn-by-2032-at-Growing-CAGR-at-5-1-Introspective-Market-Research.html
4. https://www.sciencedirect.com/topics/food-science/fish-sauce
5. https://pmc.ncbi.nlm.nih.gov/articles/PMC7866574/
6. https://sciencemeetsfood.org/love-fish-sauce/
7. https://www.tastingtable.com/857336/3-types-of-fish-sauce-and-what-to-use-them-for/
8. https://www.ciafoodies.com/ingredient-spotlight-fish-sauce/
9. https://www.myfoodresearch.com/uploads/8/4/8/5/84855864/_3__fr-2021-562_hakimi.pdf
10. https://www.nutritionadvance.com/fish-sauce-nutrition/