Nước Mắm Rươi – A Delicacy ‘Fish’ Sauce Made From Ragworms
Ragworms live in salt waters and estuaries. In North Vietnam, ragworms, such as Tylorrhynchus heterochaetus, are considered a delicacy in Vietnam where they are used in the dish chả rươi (pan-fried minced pork and ragworms). In South Vietnam, especially in Trà Vinh province, a ragworm species are used to make a delicacy fish sauce.
(In Vietnamese, nước mắm literally means the water that is dripped from fermented fish or other aquatic creatures. In English, it’s often translated as fish sauce. However, zoologically, ragworms are not fish, so the English word “fish sauce” may not be correct.)
Legend has it that King Gia Long once fled from the Tay Son rebel troops and lived with a rich family in Trà Vinh. The family owner often treated the king with the ragworm “fish” sauce. Later, when the king regained the throne, he still sent boats to Trà Vinh to buy that ragworm “fish” sauce. So, the sauce is called nước mắm ngự, literally means “the (fish) sauce for the king”.
In Tra Vinh, the ragworm species is a little different from the Northern ones. When alive, ragworms here has transparent blood red color. They live deep in saltwater, mangrove areas, along rivers, canals, and coastal alluvial plains. They have the shape of a beetle, and as small as a match.
Every year, Tra Vinh ragworms escape from their usual habitats during the windy season, when the water level rises to the shore. They are intertwined or clustered together and they floating on the water surface. Local residents use rackets with a mosquito net to catch the ragworms.
The recipe for making fish sauce from ragworms here is also simple. The ratio is 7:3, which means for 7 volume of ragworms should be fermented with 3 volume of sea salt. Ragworms should be fermented for at least 8 months, better for 10 months. Ragworm sauce should not be confused with fermented ragworm paste (Vietnamese: mắm rươi). The former has watery texture, it’s actually the water that dripps from fermented ragworms. The latter, however, has pasty texture, which includes the grounded ragworms.
In the past, ragworm sauce is often sold to local residents. Now some commercial brands including Long Vinh (Vietnamese: Nước mắm rươi Long Vinh), have appeared in some supermarkets.