Out of the corner of my eye, I noticed something twisting and turning, rhythmic and precise. It was only when I was directly in front of the Saigon street stall that I realized what was unfolding: the owner, a smiling man in his 40s who always greeted me as I walked by, was packaging nuoc cham, a condiment made from fish sauce, water, lime juice, and sugar. He was also adding thin slivers of pickled carrots to the tiny bags that piled in front of him.

What he was doing happens all over the city at street stalls and restaurants. Nuoc mam (pure fish sauce) is consumed by 95% of Vietnamese households. It’s also used to make nuoc cham, a dipping condiment of fish sauce, water, lime juice, and sugar that accompanies many Southern Vietnamese dishes.

Fish sauce packets, ready to be consumed.

In my travels, I’ve heard others cite fish sauce as one of those tastes that takes some getting used to for Western palates, along with stinky tofu and durian fruit, and the bright purple fermented shrimp paste that accompanies Vietnamese bun rieu soup. Its lingering smell leaves no mystery about its strong, fishy contents.

Used in Thailand as nam pla and Myanmar as ngan bya yay, as well as Laos, Cambodia, and the Philippines under other local names and variations, one thing is certain regardless of preference: fish sauce plays a crucial role in flavouring food in Southeast Asia.

It has become my first ingredient of choice in a new city, something I use in homemade soups and curries, chicken marinates and salads, and even omelettes, adding a taste of Vietnam to my meal. To my taste buds, it is as evocative of my years in Southeast Asia as lime, garlic and chilies.

Street side banh cuon with fish sauce for dipping.

“This is more than just a condiment,” founder of Red Boat Fish Sauce, Cuong Pham, has said. “It’s so good, it’s like gold.”

In its purest form, fish sauce is made from just two ingredients: fish and salt, fermented together for months. Despite the fact that some fish sauce labels depict squid, shrimp, or even a man carrying a giant shrimp over his shoulder (my favourite, for obvious reasons), the base formula remains the same. Both fish and salt are placed into huge vats, usually three parts fish to one part salt, and weighted down to prevent the fish from floating to the surface as fermentation begins. Once liquid begins to seep out of the fish, it is drained and reintroduced to the vat for the full fermentation process, which lasts long enough for it to reach concentration, but not so long that off-flavours develop. Usually this process takes nine months to a year, with the vats sitting in the sun as the sauce takes form.

Fish Sauce in Ancient Times

The earliest origins of fish sauce go back further than most people realize, and its actual beginnings is remarkably hard to pinpoint even in 2026.

Did fermenting fish begin as a tradition in China or Vietnam? Or as some suggest in Ancient Rome? Historians remain divided on the topic.

One such food historian, Sally Grainger, notes in her 2021 book The Story of Garum: Fermented Fish Sauce and Salted Fish in the Ancient World that despite discussions of Roman fish sauce in many publications, Roman fish sauce is not actually Roman at all: it’s Greek. Per her writing, the first recorded fish sauce was produced by the ancient Greeks along the coastline of the Black Sea, where the abundant fishery resources of the region may have been a significant factor in Greek colonisation of the area as early as the 7th century BCE.

The sauce was called gàros in Greek, and when the Romans adopted it, they transliterated the name as garum. Importantly, though, the word garum came to mean something quite specific and different from the everyday condiment most Romans actually used. Many pieces, including earlier versions of this post, conflates the true history. As Grainger explains in her book, liquamen is the standard fish sauce, made by dissolving whole small fish, often anchovies, layered with salt in a barrel or pit and left to ferment for up to four months. In contrast, garum (proper garum, not the garum that’s used interchangeably to describe ‘ancient’ fish sauce) is thicker and darker, and made from fermented fish blood and viscera. It has a distinctively dark colour and iron-rich taste. It may seem pedantic to differentiate here, but I always say words matter, and my earlier version of this post got it wrong.

The Romans actually had a whole vocabulary for fermented fish products: garum, liquamen, allec, and muria each described distinct preparations. When we compare ancient Roman fish sauce to modern nuoc mam or nam pla, we are really talking about liquamen and not garum.

Some of the fish sauce available at a Thai supermarket — there were many more!

Roman fish sauce was used across a vast geographic and culinary range. The recipes in Apicius’s cookbook De Re Coquinaria, which is available for free online, give a sense of how fundamental it was to Roman cooking: fish sauce was the ingredient that brought dishes together, and it was often used instead of salt. Pompeii was famous in ancient times for its production, and the many mentions in ancient texts and cookbooks imply a very normal, common use across the Mediterranean world. Per Sally Grainger, who in addition to her book has also created reconstructions of ancient Roman sauces, has singled out Red Boat Fish Sauce as the closest thing currently available on the market to Roman liquamen.

In a landmark 2025 study published in the journal Antiquity, scientists recovered and sequenced ancient DNA from fish bone remains at the bottom of a Roman salting vat at the Adro Vello site in northwestern Spain that was thought to be a fish-processing plant, active from the first through third centuries AD. The team successfully extracted and sequenced DNA from the small bone remains and confirmed that the primary ingredient was European sardine (Sardina pilchardus). By comparing the ancient DNA with that of modern sardines, the team found the populations of this fish during Roman times were genetically similar to those currently found in the same region, which is astounding to think about. That’s 2000 years of biological continuity!

The geographic footprint of the Roman fish sauce industry was vast. Other fish-processing ‘factories’ have been excavated in Spain, Portugal, and Northern Africa, as well as more recent discoveries near Ashkelon in Israel and at the Nabeul site in Tunisia (the ancient city of Neapolis), uncovered by a 2013 storm. In modern day cuisine, fish sauce is almost completely absent from Italian food with the exception of colatura di alici, a fish sauce still made in factories in the village of Cetara in Italy’s Salerno region.

In his piece about fish sauce in the ancient world, Declan Henesy notes:

The Carthaginians were also early makers and traders of fish sauce, producing it along the coast of the Lake of Tunis, in modern day Tunisia. A Punic shipwreck from 5th century BCE, found off the coast of Ibiza, may have been carrying a cargo of fish sauce stored in amphorae made in Gades (modern day Spain) and Tingi (modern-day Morocco). There are many early Graeco-Roman literary references to fish sauce, from writers such as Aristophanes, Sophocles and Aeschylus.

There also are literary references to the sauce from writers including Aristophanes, Sophocles, and Aeschylus, confirming its place in daily ancient life long before Rome’s domination of the region.

The decline of fish sauce in the post-Roman era had several causes, of which salt scarcity and piracy are the most commonly cited. That’s not the whole story, though. The heavy salt taxes that followed the collapse of Roman administrative infrastructure also drove up the cost of producing fish sauce, and without Roman naval protection of the Mediterranean coasts, piracy disrupted the trade routes along which both salt and finished fish sauce had flowed. As a result, production ground to a stop across much of the region.

There was also a cultural and religious dimension that is often overlooked, per Grainger. In the later Roman period when Christianity took over, many communities followed a blood prohibition. This meant people could not consume any kind of animal blood, whether from meat or fish. This prohibition is what caused stopped the actual garum (made from fish blood) from being made. In the confusion of Roman terminology, once garum stopped being used the word reverted (as words sometimes do!) to mean something else: in this case, the original Greek sauce, referred to as liquamen during Roman times. Liquamen was a staple among the general Roman population, whereas garum was only consumed by those who could afford it, usually the elite.

Back to Asia: Did Fish Sauce Originate in China?

In his book Salt: A World History, Mark Kurlansky theorises that the two fermented traditions developed independently in East and West, and that Asian fish sauce originated from an earlier Chinese tradition of fermenting fish with beans. “The sauce appears to be, as some historians believe of the domesticated pig, an idea that occurred independently in the East and the West,” he writes. “The Asian sauce is thought to have originated in Vietnam, though the Vietnamese must have taken it in ancient times from the Chinese soy sauce, in those early times when the Chinese fermented fish with the beans.” Since his book was written, the historical picture that emerged suggests fish sauce that had roots in ancient China, perhaps as far back as the Zhou Dynasty around 2,300 years ago. By 50–100 BCE demand had fallen drastically as fermented bean products rose to dominance instead. Fish sauce then became popular in Southeast Asia,  re-entering China’s palates in the 17th and 18th centuries via Vietnamese and Cambodian traders.

Some scholars like food historian Laura Kelley have argued the opposite: that Roman fish sauce was the parent of modern day fish sauce, passing along the trade routes from West to East.

“So, once again, we can identify a product that flowed from west to east and was eagerly adopted by Asians on the Silk Road. The recipes for garum changed and adapted as they moved east and became nuoc mam and nam pla according to cultural preferences and what gifts the Asian seas had to offer. Archaeologists and food scientists are working to confirm these flows and linkages, so stay tuned to this channel to learn more about garum production in the ancient world and in the kitchen of Chez Kelley.”

However,  food historian Khánh-Linh Trinh is direct in her skepticism about this theory.“There is insufficient evidence to readily support the idea that the recipe for fermented fish travelled across the Silk Road and influenced nuoc mam,” she notes. It’s not impossible, but there isn’t a historical smoking gun that would prove this theory.” A doctoral Candidate in Asian Languages and Cultures at the University of Michigan, she instead goes back to the connection to China: nuoc mam uses the same technique as Chinese soy sauce production, and similar levels of consistency and clarity as soy sauce.

A scientific paper published in the Annals of Food Processing and Preservation in 2017 also looked at the technical treatment of nuoc mam in Vietnam. Researchers at Nha Trang University’s Institute of Biotechnology and Environment note that nuoc mam is produced along Vietnam’s entire coastline, from Cat Ba in the north to Phu Quoc in the south, with meaningful differences in fish species and technology by region. Among all regional varieties, Phu Quoc nuoc mam ranks highest in quality, owing to the purity of the local Stolephorus commersonii anchovies, the early salting process, and the humid island climate. (Phu Quoc’s fish sauce was also the first product in Southeast Asia to receive a Protected Designation of Origin certification from the EU Commission.) Given the relationship between China and Vietnam, it is an easy jump to think that Vietnam could have used the technique from ancient Chinese soy sauce and then applied it to what was readily available in Vietnam: fish.

Back to Declan’s piece, where he notes that while some historians claim fish sauce was introduced to Asia via the Silk Road, others think it was independently invented.

Either or both may be true. Interestingly, in 2010 CE, a team of researchers analysed samples of garum taken from containers preserved at Pompeii. They found that Roman fish sauce from the 1st century CE had an almost identical taste profile to those produced today in southeast Asia.

The reality is: we don’t know whether liquamen and nuoc mam are relatives, or twins that were separated at birth. Either way, it’s not a stretch to think of how people may have used the same logic to start fermenting a perishable good to make an umami sauce that helped food taste better. And Trinh also reminds us that the origins debate, however fascinating, is somewhat beside the point for those who grew up with the sauce. She points out that nuoc mam features in the Vietnamese creation myth itself: the story of Dragon Prince Lạc Long Quân, whose totem was a fish. “This indicates that regardless of whether nuoc mam was actually around in Vietnamese prehistory, Vietnamese conceptions of national identity certainly chose to project nuoc mam back into that history as a key token of what it means to be Vietnamese.”

Her perspective is echoed by writer Trần Ngọc Thêm, whose book Cơ sở văn hóa Việt Nam (The Foundation of Vietnamese Culture), includes the following sentence (translated): “for Vietnamese people, a meal without fish sauce is considered incomplete.”

After all the history and debate about origins, that feels like the only answer that really matters.

While we travel for the people and the culture, for the stories and the food, we sometimes take the origins of individual ingredients, like fish sauce or chili peppers, for granted.

If this short overview of fish sauce was interesting you might want to read:

• Mark Kurlansky, Salt: A World History — The foundational popular history of salt and its role in human civilization, including fish sauce.
• Veronica Meewes, The Fish Sauce Cookbook — A practical guide to cooking with fish sauce across many traditions.
• Sally Grainger, The Story of Garum: Fermented Fish Sauce and Salted Fish in the Ancient World — A scholarly treatment of ancient fish sauce, and an option for anyone who wants to go deeper than this short piece. Also available as an eBook.
• The History of Ketchup, by Dan Jurafsky — A delightful piece tracing ketchup’s origins back through fermented fish sauce.
• Espregueira Themudo et al., “Roman Atlantic garum: DNA confirms sardine use and population continuity in north-western Iberia,” Antiquity (2025) — The 2025 ancient DNA paper that confirmed the species used in a Roman-era Spanish fish-factory.
• World History Encyclopedia: Fish Sauce in the Ancient World — A well-sourced overview.
• Vegan fish sauce recipe via The Kitchn — For those who don’t eat fish.

Bon Appetit!

-Jodi