The fish sauce making process in Phu Quoc is a closed cycle, from catching the anchovies to bottling the finished product.

Anchovy-catching boats often operate in pairs for efficient fishing along the current. From June to October of the lunar calendar each year, the boats follow the currents of the fish. The anchovies are brought to the boat’s deck, cleaned with seawater, and impurities or other fish are removed. The fish are then drained, measured by baskets, and placed on the boat's floor. The fish are mixed with salt in a ratio of 2.5 to 3 fish per 1 unit of salt (2.5 to 3 tons of fish per 1 ton of salt). Each time the salt is added, a small wooden rake is used to mix it evenly, ensuring the fish do not spoil. After mixing, the fish are placed in the ship’s hold, covered with a 5cm layer of salt, sealed tightly, and the excess liquid (brine) is drained into containers. This step is called "fake salting."

Fermentation (real salting): The speed and timing of this process depend on the salting conditions, ambient temperature, and salt concentration. Once the fish arrive at the "house thung," they are poured into fermentation barrels. After 3-4 days, the brine is drained, the surface of the fish is leveled, and a 2-3cm layer of salt is added. After 3-4 more days, pressing is done with wooden pins. Then, the brine is pumped back over the surface. This self-fermentation process continues for 12 months in the barrels under natural conditions. During the fermentation, the fish sauce makers monitor the fermentation process to prevent spoilage and address any issues like sourness or spoilage. With generations of experience, the fish sauce makers have developed techniques for dealing with problems such as sour or blackened fish sauce or spoiled fish.

Draining the fish sauce: After the fermentation is complete, the fish sauce is drained from the barrels. There are two stages for draining:

• Extracting the base fish sauce: When the liquid in the fermentation barrel turns a golden brown and gives off a fragrant aroma, the fish sauce is ready to be extracted. The maker opens the spout to let the sauce flow slowly into containers. After draining all the liquid, the pressing board is removed, cleaned, and pressed again. The extracted fish sauce is then pumped back into the barrel. This process is repeated until the fish sauce becomes golden-red, clear, and thick, with no sediment. The fish sauce should have a mild fragrance and a rich, umami flavor—this is considered the highest quality product, which is ready for bottling.

• Extracting long fish sauce: After all the base fish sauce has been drained, salt is dissolved in clean water until it is saturated, and the brine is pumped through the barrels that have already had their base sauce drained. The brine is circulated through the barrels from low-protein to high-protein fish sauce. The final product, called long fish sauce, is collected through several cycles of brine extraction, with the process taking 2-3 months.

Mixing fish sauce to create the final product:

The final fish sauce products include: Base fish sauce (cốt y), which is pure fish sauce, unblended, with protein content from 430N; Type 1 fish sauce (nước nhứt), which is blended fish sauce with a protein content of 400N – 350N; Type 2 (nước nhì), with a protein content of 350N – 200N; and Type 3 (nước ba), with a protein content of 200N and below. To make 20 liters of 350N fish sauce, the mixing ratio is 3 parts base fish sauce (400N) to 1 part long fish sauce (200N). For Type 1, Type 2, and Type 3 fish sauce, the ratio of base fish sauce decreases, while the amount of long fish sauce increases.

Bottling: The finished fish sauce is extracted into containers of varying sizes for market distribution. Today, Phu Quoc fish sauce is bottled using modern, automated processes. The fish sauce is pumped from the storage tank through a system into glass or plastic bottles, with the volume controlled by employees. The bottles are then capped, labeled, and packed into boxes according to standards.

Phu Quoc fish sauce has a golden brown to amber color, clear and not cloudy; a light fragrance; a salty, sweet, and umami flavor with a rich taste of natural protein and fish oils; and a protein content from 20gN/liter to 43gN/liter.

Phu Quoc fish sauce is the result of many factors, such as the quality of the fish, salt, water, the unique climate of Phu Quoc Island, the method of caring for the sauce, and the knowledge of the fish sauce makers passed down through generations.

The fish sauce making profession in Phu Quoc is closely tied to the sea and local maritime beliefs, such as the worship of the Whale God, sea gods, and Mẫu Thủy (the Goddess of the Sea). Phu Quoc has many temples dedicated to the Whale God, including three main worship sites in Duong Dong, Duong To, and An Thoi; the Thuy Long Temple (Dinh Ba Thuy Long – Duong Dong); and Dinh Cau, also known as the Long Vương Temple, located on a small hill at the mouth of the Duong Dong River (also called Gành or Hill).

The fish sauce making profession in Phu Quoc is intertwined with the daily lives of the local people and the development of the island and the Kiên Giang province. The profession has significantly impacted the economy of the local population in Phu Quoc and the fishermen in the southwestern seas. Phu Quoc fish sauce is a product of cultural exchange and adaptation within Vietnam. The profession was brought to Phu Quoc by Vietnamese settlers from Central Vietnam and has flourished in this new land. One of the most prominent cultural marks passed down through generations in Phu Quoc is the coastal culture, with the whale worship, the worship of river and sea gods, culinary traditions, and the art of fish sauce making. The fish sauce profession reflects the local cultural identity, with traditional knowledge, secrets, and techniques passed down through many generations. Fish sauce, aside from being used as a seasoning and food ingredient, is also used in traditional medicine to treat various ailments such as calming the mind, lowering blood pressure, restoring vitality, treating goiter, asthma, joint pain, and weak children. Fishermen in Phu Quoc often drink a small cup of fish sauce to boost energy and stay warm when diving deep into the sea. The fish sauce making profession in Phu Quoc has economic and tourism value, attracting visitors to learn about the local craft and culture.