Clem's Fish Sauce
 
 
 

A pungent and savoury brew arising from rotted down fish has long been a culinary flavour ingredient through time. The ancient Romans made a product called garum which was simply fish, salted and allowed to ferment for weeks after which a liqiud was tapped for use in cooking. If this sounds like the fish sauce that we are familiar with today, it is because that is what fish sauce is.

As a fermentation microbiologist, I have always said that the ancients and the poor had ways in which they increased the nutritional value of their foods by simply allowing controlled rotting. By controlled, I mean the breakdown action by "good" rather than "bad" microbes. The breakdown products are more digestible/nutritive substrates (amino acids versus native proteins), essential nutrients such as vitamins, and importantly, flavour compounds which impart umami to one's taste buds.

In Vietnam, the island of Phu Quoc is the home of the country's famous fish sauce. It has European Union Protected Designation of Origin (PDO) and was Vietnam’s first product with Geographical Indication (GI) status.

The production of traditional Phu Quoc fish sauce starts with the island's Black Anchovies being immediately salted after being caught before the fish are even landed. The process continues on land where the salted anchovies are fermented in braided bamboo barrels for between a year to year and a half. Every now and then, the amber liquid which begins to form is tapped at the bottom of the barrel and returned to the top to make for mixing of the fermenting brew.

At the end of the brewing, the first tapping is the most prized. Further tappings may or may not include the use of salt water to help extraction. The process seems rather simple to replicate but the uniqueness of each country/region's fish sauce can be attributed to the fish used (and their diets), the type of salt, the barrelling, the brew time and so on. Premium fish sauces will have their oN value displayed on their labelling. The higher the N value, the higher the total nitrogen content in g per litre. The N value is a measure of how much protein is indicated in the sauce. The higher the protein content, the better supposedly is the sauce (other things being equal).

I was surprised by finding fresh anchovies at a fish monger today. I have been on the look out for them for a couple of years and haven't seen them until today. So I bought 1 kg to make my very own first fish sauce - something I have wanted to do for a long time.

Using researched methodology, here's is the first blog (follow ups to come through the ferment) of how I made my fish sauce:

NOTE:
You are making a food product.
Practice personal and prep area hygiene; use clean utensils and containers.
 

  1. Wash the anchovies well through several changes of water until there is no trace of blood or fish scales.

 

  


Australian anchovies after washing
 
 
  1. Drain all water from the fish (important so that the added salt is not diluted).
     
  2. For 1 kg of fish, you need 333 g of natural sea salt (not iodized).
    The ratio of fish to salt is 3:1.
    Use 300 g of salt to mix in and the rest to layer on top of the packed fish later.
    The amount of salt is critical for (a) the end saltiness of the fish sauce - not good to be too salty (b) creating the correct environment to deter pathogenic bacteria while allowing beneficial halophillic bacteria to proliferate and breakdown the fish proteins and fats.

 

  


The anchovies after mixing in with salt
 
 
  1. Mix well and then place the salted fish into a container with a lid.
    Pack the fish down tight and layer the last of the salt over the top.
     
  2. Close the lid tightly to prevent smells escaping and pests crawling in.
    You may need to "burp" the lid every now and then to let any gases formed escape.
     
  3. Leave the jar of fish to ferment in a warm corner of your house for at least 12 months; more if you have patience.
    In a place with winter, fermentation will be slower.
    The 12 - 18 months used by the Vietnamese is practice in a rather warm climate.

 

  


This is Day 0
Salted anchovies deposited in the fermentation jar
They will be left to ferment for at least 12 months
 

 

I shall make updates on the progress of fermentation in the following months.

 

 

 

 

www.clemkuek.com

 

31 July 2026
 

 



Created by Clem Kuek