Fish sauce production in Southeast Asia extends across Thailand, Vietnam, Cambodia, Laos, and the Philippines — each producing distinct variations. Thai fish sauce is made from anchovies (pla kra-tek) fermented in salt for 12–18 months, then pressed and the liquid extracted. The first pressing (the highest quality) is the most complex. Thompson specifies Tiparos and Megachef as quality brands available outside Thailand. [VERIFY] Thompson's specific brand recommendations.
Fish sauce — nam pla — is the universal salt of the Thai kitchen. It is not merely a salty liquid: it is a fermented preparation of extraordinary complexity, containing the full range of umami nucleotides and glutamic acid compounds that plain salt cannot supply. The brand and quality of the fish sauce used determines a large part of the Thai dish's background depth — a high-quality fish sauce adds an almost imperceptible but structurally important umami foundation to every dish. A poor-quality fish sauce adds a sharp, overly pungent, ammonia-edged salt note that dominates rather than supporting.
Fish sauce's inosinic acid (from the fermented anchovy's breakdown of ATP) is a nucleotide umami enhancer — as Segnit notes, nucleotide umami compounds (found in fish sauce, bonito, anchovies) synergistically amplify glutamate-based umami by a factor of 5–8 when combined with a glutamate source (such as the tomatoes in som tam or the shrimp paste in a curry). This synergy is the reason that Thai cooking's combination of fish sauce and shrimp paste produces a deeper, more complex savoury depth than either alone at equivalent concentrations.
**Quality indicators:** - Colour: amber to light brown — not dark brown or black (both indicate over-fermentation or old stock). - Smell: complex, pungent, fishy but not ammoniac. The smell should be intensely marine and deeply savoury — not merely sharp and unpleasant. Press the bottle and smell: a good fish sauce smells of the sea in a complex way; a poor one smells of ammonia. - Taste (a single drop on the finger): immediately salty, then a wave of deep, complex savouriness — inosinic acid and glutamic acid compounds delivering the umami amplification effect. A poor fish sauce tastes only of salt and fish. **Usage:** - Fish sauce is the primary salt in almost all Thai dishes — used in place of table salt throughout. - Measurement: most Thompson recipes give fish sauce quantities in tablespoons. The quantity can vary with the brand's concentration. - Never substitute: soy sauce does not produce the same result. The glutamic acid compounds in soy sauce and the inosinic acid in fish sauce are different in their flavour effect. - At service: a small dish of fish sauce and sliced fresh bird's eye chillies (prik nam pla) is the standard tableside condiment — chilli-infused fish sauce used to season everything at the table. Decisive moment: The moment of final seasoning calibration in a dish — adding fish sauce in increments, tasting after each, aiming for the level at which the dish's other flavours (sour, sweet, spicy) are amplified and present without the salt being detectable as salt. The correct level of fish sauce: all other flavours are suddenly more vivid, more perceptible, without any saltiness in the foreground. Exceeding this level: the salt becomes the primary note.
David Thompson, *Thai Food* (2002); *Thai Street Food* (2010)