Scale it up with fish sauce

Use this Southeast Asian staple to add a boost of flavour to everything from roast chicken to greens

Like a musical ear-worm, a particular flavour combination sometimes lodges in your brain and plays over and over. Despite coming from Northern Ireland – where I grew up with the salty richness of butter, the floury sweetness of potatoes and the peatiness of whiskey – you’d think I’d been brought up in Hanoi. Perhaps, in another life, I was. The imagined flavours that chase each other round my head are the hot, sour, salty, and sweet strains of chilli, lime, fish sauce and palm sugar, the tastes of Southeast Asia. Fish sauce is the ingredient that makes Southeast Asian food what it is, the salty, amber river that runs through it. In Thailand it’s nam pla, in Vietnam nuoc mam, in Myanmar ngan bya yay.

I first tasted fish sauce in a living room in London’s Maida Vale in 1986. There were no supper clubs back then, but a neat middle-aged Vietnamese lady had turned her home into a restaurant. The rice paper rolls looked as if they’d been made by an artist, little furls of colour wrapped in damp translucence. I dipped one in nuoc cham, a Vietnamese dipping sauce based on fish sauce. Salt, heat and sugar – fireworks. I was immediately hooked.

In its purest form, fish sauce is made by pressing layers of anchovies and salt. The liquid that seeps out is drained off and added back to the tank for full fermentation to begin, a process that takes nine months to a year. The resulting sauce isn’t just fishy and salty, it’s also funky and deeply umami. Some think that Thai fish sauce is a little rough, and very salty (in the words of cookbook author Andrea Nguyen, it’s ‘for the lusty highs and lows of Thai food, not the rolling hills and valleys of Viet food’). Fish sauce die-hards tend to prefer the Vietnamese stuff, specifically that which is made on the island of Phú Quoc (and even more specifically, the Red Boat brand).

Some cooks use fish sauce in other cuisines, and you can’t argue with the wisdom of this. After all, garum, the fish sauce (made either with whole fish or fish guts) of ancient Rome, was used as a seasoning. Why shouldn’t you use it to deepen your pot of ragu? The production of fish sauce in the Mediterranean stopped when salt became expensive. In his book Salt: A World History, Mark Kurlansky suggests that Asian fish sauce isn’t connected to garum. Rather, he theorises that both sauces developed simultaneously, although we don’t know for certain. I do know, however, that using fish sauce in food pulls flavours together and gives it an umami hit. It deepens and brightens. There are evenings, if my fish sauce craving is high, when I set about supper with all the excitement of a bear after a trout. I stir-fry prawns with chilli, lime, ginger and fish sauce, and throw a little sugar in at the end. Sometimes I don’t even cook: I just make nuoc cham and dip raw salmon and shavings of pineapple into it. Really, I’ve got it bad.