Tom Som — Sour Tamarind Fish Soup / ต้มส้ม

Ingredients

• 400 g whole small fish, 100–150 g each, cleaned and scaled; or fish steaks of equivalent weight
• 750 ml water
• 80 g tamarind block, soaked in 250 ml warm water, strained to yield tamarind water
• 40 g fresh ginger, peeled, cut into fine julienne strips
• 60 g shallots, peeled, halved or sliced
• 30 g galangal, peeled, sliced into thin coins
• 2 tbsp fish sauce, or to taste
• 1 tsp palm sugar, or to taste
• 15 ml lime juice, freshly squeezed, added at seasoning stage

Method

1. 1
   Soak the block tamarind in 250 ml of warm water for ten minutes, working it with the fingers until fully dissolved, so the pulp releases its sourness evenly rather than leaving pockets of concentrated paste in the finished broth. Pass through a fine sieve, pressing firmly to extract all pulp, and discard the solids. The resulting liquid should be a translucent amber colour, not opaque — opacity signals undissolved pulp that will muddy the soup.
2. 2
   Bring 750 ml of water to a gentle simmer in a medium saucepan, then add the sliced galangal and halved shallots, so they surrender their fragrance slowly and the broth builds a clean, rounded base rather than a raw, sharp one. Simmer for five minutes, skimming any foam that rises, until the aromatics have begun to soften. The broth should look clear by the time the tamarind water goes in.
3. 3
   Add the tamarind water and fish sauce, then stir in the palm sugar, so the sugar tempers the raw bite of the tamarind before the fish ever touches the pot. This is where the dish lives or dies: without palm sugar in proper proportion to the tamarind, the acidity will be harsh rather than bright — add the sugar in small increments and taste after each addition until the sourness lifts rather than bites. The broth should read bright and cleanly sour, with a sweetness that rounds the acidity without masking it.
4. 4
   Add the julienned ginger to the broth without vigorous stirring, so the strips hold their shape and release their warmth gradually rather than fraying into fibrous threads that cling to the fish. Simmer for two minutes until the ginger contributes a faint peppery warmth to the steam rising from the pot. The strips must remain visually intact in the finished bowl.
5. 5
   Lower the fish gently into the simmering broth so the flesh cooks evenly without breaking apart before it is done. Small whole fish of 100–150 g need only three to four minutes in the acid-soured broth, which speeds the cooking noticeably compared with a plain stock — watch the flesh at the thickest point and press it lightly with a spoon; it is ready when it yields cleanly from the bone. Do not rush this with higher heat, or the skin will split and the broth will cloud with released fat.
6. 6
   Remove from heat and add the lime juice, so its fresh, volatile brightness stays in the bowl rather than cooking off into flatness. Correct the seasoning with a final small measure of fish sauce if needed. Do not return the pot to the boil after the lime juice is added, as the broth will cloud and lose the golden clarity that tells the diner the soup is properly made.