The Sauce That Changes Its Recipe Twice A Year

About 15 kilometres northwest of the city centre, where the road starts to climb toward the Hai Van Pass, there is an old fishing village called Nam O. It sits directly on Da Nang Bay. Boats land anchovy on the sand, and behind the houses stand rows of clay jars with weights pressing down on what is inside. In each jar, fish is slowly turning into sauce.

There are two ingredients and no others. Black anchovy, called ca com than, caught in the water off Da Nang. And salt, which the makers here buy only from Ca Na in Ninh Thuan province and Sa Huynh in Quang Ngai province. No water, no sugar, no colouring.

The anchovy arrives twice a year. Once in the second and third lunar months, and again in the seventh and eighth. That is where the two recipes come from. In the earlier season there is little rain, the sea holds more salt, and the fish is firm, so the makers use three parts fish to one part salt. In the later season the rain comes, river water runs down into the sea, the sea holds less salt, and the fish is softer. So they add more salt, two and a half parts fish to one part salt, to stop the batch from going bad. Families here learned this by making it, season after season, and both numbers are now written into the official rules for the name Nam O.

Then it is only waiting. The salt goes in once, at the start. For the first three months the fish is pressed down. After that it is stirred, so the bones and the flesh break down evenly. Twelve to eighteen months later the sauce has turned dark amber and it is filtered. To carry the Nam O name it must hold at least 20 grams of total nitrogen in every litre, and it has to be bottled inside the village.

Official recognition came very late. On August 27, 2019, the Ministry of Culture, Sports and Tourism named the making of Nam O fish sauce a national intangible cultural heritage. In June 2024 the sauce received geographical indication certificate number 00138. It was the first one ever granted to anything in Da Nang, and only the third for fish sauce in the whole country, after Phu Quoc and Phan Thiet.

The trade is smaller than it used to be. In early 2024 the village association counted 69 members and about 220 people working, producing 200,000 to 300,000 litres a year, and the association had lost close to 71 households since it was founded.

So go, buy one bottle in the village, and eat it the way people here do. One spoon over hot plain rice and nothing else. It is salty first. Then, a second later, a sweetness arrives at the back of your mouth and stays. That sweetness is what the twelve months were for.