Yam Som-O

the Thai salad of the grapefruit's parent: pomelo broken into its dry separate juice sacs, dressed with palm sugar, fish sauce, and lime, and finished with toasted coconut, fried shallots, and prawns

Origin: Thailand

From the journey of Pomelo.

Som-o is the pomelo, Citrus maxima, and it is the fruit from which half the grapefruit's genome comes. Thailand grows it in quantity, above all around Nakhon Chai Si west of Bangkok, and treats it as a savoury ingredient far more often than a sweet one. The dish works because of a structural peculiarity that separates the pomelo from every other citrus. Its flesh is made of large, firm, comparatively dry juice sacs that come apart cleanly and stay apart. Break a segment open and it falls into what looks almost like a coarse grain, and that grain holds its shape under a dressing instead of dissolving into juice. A grapefruit cannot do this: its sacs are thin-walled and wet, and the moment they meet salt and acid they collapse and flood the bowl. The substitution is therefore not available, and this is the clearest culinary demonstration that the pomelo and the grapefruit are different ingredients rather than sizes of the same one. The dressing is the standard Thai yam balance of salt, sour, sweet, and hot, and its proportions are adjusted to the fruit rather than fixed. A sweet pomelo takes more lime; a sharp one takes more palm sugar. The toasted coconut and the fried shallots are not garnishes but the textural half of the dish, and both should be added at the last possible moment.

Ingredients

Salad

  • 1 large pomelo, ripe and heavy for its size
  • 200 g raw prawns, peeled and deveined
  • 60 g desiccated or freshly grated coconut
  • 4 tbsp crisp fried shallots
  • 40 g roasted peanuts, roughly crushed
  • 1 handful coriander leaves and mint leaves, torn

Dressing

  • 3 tbsp fish sauce
  • 3 tbsp palm sugar, shaved
  • 3 tbsp lime juice, freshly squeezed
  • 2 whole red bird's eye chillies, finely sliced
  • 2 tbsp coconut cream

Method

  1. Score the pomelo rind from top to bottom in quarters and pull the thick pith away in sheets. Separate the segments, peel the tough membrane from each one, and break the flesh apart into loose clusters of juice sacs.
  2. Toast the coconut in a dry pan over a medium heat, stirring constantly, until it is evenly golden and smells nutty. Tip it out at once onto a cold plate.
  3. Poach the prawns in lightly salted simmering water for two to three minutes until just opaque, drain, and cool. Cut the larger ones in half lengthwise.
  4. Warm the palm sugar with the fish sauce over a low heat until dissolved, then take off the heat and stir in the lime juice, chillies, and coconut cream. Taste and adjust.
  5. Put the pomelo and prawns in a wide bowl, pour over the dressing, and turn everything gently with your hands two or three times only.
  6. Scatter over the toasted coconut, fried shallots, peanuts, and herbs, and serve immediately.

Notes

Grapefruit is not a substitute here and the dish should not be attempted with it: grapefruit sacs are thin and wet, and they collapse into juice the moment the dressing goes on. If pomelo is unavailable, make something else. Buy a pomelo that feels heavy and has a slightly yielding, faintly oily rind; a very light one is dry inside. Thai cooks often add shredded poached chicken alongside or instead of the prawns, and a vegetarian version replacing the fish sauce with light soy and the prawns with fried tofu is common enough in Bangkok. Serve as one dish amongst several with rice, not as a first course on its own.

The Gastrographer

The Gastrographer

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Journey Point Map Key

Ingredient originTrade or transit route
Became a culinary stapleColonial / trade control
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