Thai cooking is not a cuisine of recipes — it is a cuisine of flavour balance. Every preparation, from a simple dipping sauce to a complex curry, is an exercise in calibrating four elemental forces: salt (from fish sauce or shrimp paste), sour (from lime juice, tamarind, or green mango), sweet (from palm sugar, and less commonly coconut milk or fruit), and heat (from fresh and dried chillies). No ratio is fixed. The cook tastes and adjusts continuously — adding fish sauce here, a few drops of lime there, a pinch of palm sugar to round a sharpness — until the preparation achieves a state of balance that Thompson describes throughout his work as 'rounded and complete'. This balancing act is the decisive technique in all Thai cooking. Every entry in this database is, at its foundation, an application of these four forces.
As Segnit notes, fermented fish sauces (from pla ra to nam pla to the Vietnamese nuoc mam and Korean myeolchi aekjeot) all share the same chemistry — the proteolytic breakdown of fish protein during fermentation produces a compound mixture of amino acids, peptides, and volatile amines that delivers umami with a intensity that no fresh ingredient replicates. The specific flavour of each varies by the fish species used, the fermentation temperature, and the duration — but the mechanism is universal. Thai fish sauce paired with lime juice is the Thai kitchen's equivalent of the French kitchen's acid-plus-salt seasoning system: the fish sauce's amino acids (glutamic acid, particularly) are amplified by the lime's citric acid in a chemical interaction that makes the combined seasoning more effective than either used separately.
David Thompson, *Thai Food* (2002); *Thai Street Food* (2010)