Tom yum is the clear, hot-sour Thai soup: a broth infused with lemongrass, galangal, and kaffir lime leaves, tinted brick-red with roasted chili paste, sharpened with lime juice off the heat, and finished with shrimp added at the very end so they stay tender. It reads sour first, then salty, then hot.
This is the clear style (tom yum nam sai). The creamy restaurant style adds coconut milk (tom yum nam khon) — a different recipe, not a variation of this one.
Ingredients
Serves 4.
- 1 lb (450 g) large shrimp, shell-on, peeled and deveined (reserve the shells)
- 4 cups water or chicken broth
- 3 stalks lemongrass, tough outer layers removed, cut into 2-inch pieces and smashed
- 4 thin slices fresh galangal (about a 1-inch piece)
- 5 kaffir lime leaves, torn
- 1 cup straw mushrooms or sliced button mushrooms, drained if canned
- 1 tbsp roasted chili paste (nam prik pao)
- 4 Thai bird’s eye chiles, lightly crushed (to taste)
- 1 1/2 tbsp fish sauce, to taste
- 2 tbsp fresh lime juice, to taste (added off the heat)
- 1/4 cup cilantro leaves, roughly chopped, for serving
- 2 green onions, sliced, for serving (optional)
For serving: cooked jasmine rice.
Method
- Peel and devein the shrimp, keeping the tails on if you like. Reserve the shells.
- Make the shell broth (optional but recommended). Put the shrimp shells in a pot with the water, bring to a boil, then simmer 10 minutes. Strain and discard the shells. (If using chicken broth instead, skip to step 3.)
- Return the broth to the pot. Add the lemongrass, galangal, kaffir lime leaves, and chiles. Bring to a boil, then simmer gently 8 minutes until fragrant. Think of this like making tea — a gentle infusion, not a hard boil.
- Add the mushrooms and the roasted chili paste; stir to dissolve the paste. Simmer 2 minutes.
- Add the shrimp and cook 3 minutes, just until pink, firm, and opaque. Do not overcook — shrimp go rubbery fast.
- Take the pot off the heat. Stir in the fish sauce and lime juice; taste and adjust — the soup should read sour first, then salty, then hot. Add the cilantro and green onions.
- Ladle into bowls, leaving the lemongrass stalks, galangal slices, and lime leaves behind in the pot or pushed to the side of the bowl. Serve with jasmine rice.
Tips and ingredient notes
- Which aromatics you eat: lemongrass stalks, galangal coins, and whole kaffir lime leaves are flavoring agents — fibrous, woody, and unpleasant to chew. Diners push them aside.
- Nam prik pao (roasted chili paste): gives the broth its brick-red tint and smoky depth. Sold in jars at Asian markets; do not confuse it with sambal oelek or sriracha.
- Galangal vs. ginger: galangal is piney, citrusy, and sharp; ginger is hotter and sweeter. Ginger is not a 1:1 substitute — it changes the soup’s character.
- Kaffir lime leaves: fresh or frozen from Asian markets; dried leaves are a weaker substitute. Tear them to release the oils.
- Mushrooms: straw mushrooms (canned, drained) are the classic; button or oyster mushrooms are fine substitutes.
Storage and food safety
Allergen note: contains shellfish (shrimp) and fish (fish sauce). Shrimp must be cooked until pink, firm, and fully opaque — 145°F (63°C) internal temperature (FoodSafety.gov). Serve within 2 hours; refrigerate leftovers promptly and reheat until steaming hot.