As the name suggests, fish sauce is made of fish. There are many different methods to produce this protein-rich liquid, used widely in Asian cuisine. But did you know, fish sauce was a favorite in the cuisine of ancient Rome?
When the Roman Empire disappeared, fish sauce disappeared from European cuisine. Except for that Roman outpost of Great Britain where it still is a favorite flavouring in the form of Worcester sauce!
In the Khmer language, fish sauce is called ‘toeuk trey’ (literally ‘fish water’). In Thailand it is called ‘nam pla’, in Vietnam ‘nuoc nam’, in the Philippines ‘patis’, and in Indonesia it is known as ‘ketjap ikan’. Fish sauce can be made of either freshwater or saltwater fish.
Today, most commercially made fish sauce is made from saltwater fish, but the home made fish sauce in Cambodia is made from fish caught in the vast Tonle Sap lake, the largest freshwater body in Southeast Asia. The pungent Cambodian fish paste called ‘prahok’ is also made from small fish caught in the Tonle Sap.
For good quality fish sauce, the fish are rinsed, drained and mixed with salt. They are then filled into large vats. In the traditional method the jars are covered with a bamboo mat topped with heavy weights to prevent the fish from floating when the water inside them is extracted. Modern commercial production of fish sauce is usually done in large, concrete containers.
The jars are left in a sunny location for quite a long time, usually from nine months to a year. Every now and then the jars are uncovered to expose the fish to direct sunshine. This process is essential for fish sauce of superior quality.
After the fermentation process, the liquid is removed from the jars and filtered. The filtered liquid is put into other (clean) jars. These jars are not covered, the sauce is allowed to air out and dissipate the strong fish odors. After a couple of weeks, the sauce is ready for bottling. Fish sauce made this way is of the highest quality and has a clear, reddish brown colour.
Like e.g. olive oil, there are different qualities of fish sauce. The above described method is the ‘first pressing’ of fish sauce. The extended fermentation process reduces the intense fishy smell and taste. Fish sauce is often mixed with ingredients like citrus juice, sugar, herbs and spices.
Second grade fish sauce is made by adding salt water to the fish remains after the ‘first pressing’ and letting the jars sit for another two or three months before filtering. The lowest grade is made by boiling fish remains with salt water. However, these second and third grade sauces are usually mixed with some of the first grade to improve flavour and colour.
How to find good quality
So, how to select a good quality fish sauce? Sometimes the highest quality (the ‘first pressing’) is mentioned on the label, but more often than not it will be in a language you cannot read.
Fortunately there are other methods to judge the quality of the fish sauce.
Most importantly, the colour. Compare the colours of fish sauces on the shelf and look for sauce with a clear, amber-red colour. Darker fish sauces are either lower quality or bottles that have been stored for too long.
Secondly, higher quality fish sauce is for sale in glass bottles, not plastic bottles.
And finally, the price. Higher quality fish sauce of course is more expensive than lower quality. But be cautious here, the most expensive fish sauce on offer is not necessarily the best.