Tom kha gai is a Thai coconut soup made with chicken, galangal, lemongrass, and kaffir lime leaves simmered in coconut milk, finished with lime juice, fish sauce, and chilies. It shares its aromatic backbone with tom yum but trades the clear, sour broth for a rich, coconut based one, which softens the sourness and heat without erasing them. Galangal, not ginger, is the defining aromatic here, giving the soup a citrusy, piney sharpness that ginger doesn't replicate.
The dish likely developed as a regional variation once coconut palms became a staple crop across central and southern Thailand, adapting the tom yum formula to the ingredients on hand. It has become one of the more internationally familiar Thai soups because the coconut milk makes it feel gentler on first sip, even though the aromatics underneath are just as assertive as in tom yum.
This recipe keeps the coconut milk from separating by adding it gradually and never letting the soup hit a hard boil after that point.
What Actually Matters
Simmer, never boil, once the coconut milk goes into the pot. A hard boil breaks the fat out of the coconut milk, leaving an oily, grainy soup instead of a smooth one. Keep the heat at a gentle simmer from the moment the coconut milk is added through to serving, and the soup stays silky. This single habit separates a good tom kha gai from a broken, separated one.
Tom Kha Gai Recipe
Serves 4. Prep time: 15 minutes. Cook time: 25 minutes. Total time: 40 minutes.
Ingredients
- 2 cans (13.5 ounces each) full fat coconut milk
- 2 cups chicken stock
- 1 pound boneless chicken thigh, sliced thin
- 3 inches galangal, sliced into thin coins
- 2 stalks lemongrass, bruised and cut into 2 inch pieces
- 6 kaffir lime leaves, torn
- 8 ounces mushrooms, sliced
- 3 tablespoons fish sauce
- 2 tablespoons fresh lime juice
- 1 tablespoon palm sugar
- 2 to 3 Thai bird chilies, lightly smashed
- 1/4 cup cilantro leaves, for garnish
Method
- Bring the chicken stock to a simmer in a pot. Add the galangal, lemongrass, and lime leaves. Simmer for 8 minutes to infuse.
- Add the chicken and mushrooms. Simmer for 5 minutes until the chicken is nearly cooked through.
- Reduce the heat to low and pour in the coconut milk. Warm gently, never letting it come to a full boil.
- Stir in the fish sauce and palm sugar. Simmer gently for 5 minutes until the chicken is fully cooked.
- Remove from heat and stir in the lime juice and chilies.
- Taste and adjust: more lime for sour, more fish sauce for salt, more chili for heat.
- Ladle into bowls and garnish with cilantro.
| Nutrient | Per Serving (estimated) |
|---|---|
| Calories | 390 |
| Protein | 25 g |
| Fat | 28 g |
| Carbohydrates | 10 g |
Estimate calculated from the ingredients above, not a lab verified value.
Tips and Variations
Swap chicken for shrimp and reduce the simmer time for shrimp to just 3 minutes so it doesn't overcook. Dried galangal reconstituted in warm water works if fresh isn't available, though the flavor is milder. This soup freezes less well than most because the coconut milk can separate on thawing; it's best made fresh or refrigerated for a couple of days.
Frequently Asked Questions
Can I substitute ginger for galangal?
You can in a pinch, but the flavor changes noticeably. Galangal is more citrusy and piney, while ginger is spicier and sharper; they aren't interchangeable if you want the traditional taste.
Why did my soup turn oily?
The coconut milk was boiled too hard, which breaks the emulsion. Keep the heat at a gentle simmer once the coconut milk goes in.
Is tom kha gai spicy?
It has heat from the chilies, but the coconut milk mellows it considerably compared to tom yum. Adjust the chili count to taste.
Can I make this vegetarian?
Yes, use vegetable stock, swap the chicken for tofu and extra mushrooms, and replace fish sauce with soy sauce for a similar salt profile.
How long does it keep in the fridge?
Up to three days in an airtight container. Reheat gently over low heat rather than a hard boil to keep the coconut milk from separating.
For more Thai cooking, see the Thailand recipes hub. For a pot that holds a gentle simmer without scorching, check pots, pans, and cookware or browse kitchen essentials.
I'm Chef Alan. I have spent 35 years in professional kitchens, I have formal culinary education in New Hampshire, and I have been honored as a 6-Time 4-Diamond Chef. More about me here.
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