Central Sour Curry with Shrimp (Gaeng Som Goong)

Ingredients

Equipment Needed

• •Heavy granite mortar and pestle (krok), at least 8 inches diameter
• •Medium pot or saucepan
• •Fine mesh strainer for tamarind

Instructions

1. 1

   Pound the kreung tam

   Drain the soaked chilies and squeeze out excess water. In a heavy granite mortar (krok), start with the salt and chilies. Pound to a rough paste. Add the shallots and pound until they break down into the chili paste. Add the turmeric and pound until integrated. Finally, add the kapi and pound everything together until you have a uniform, slightly coarse paste. It should be vibrant orange-red with flecks of shallot still visible. The smell should hit you: fermented, sharp, alive. That's the kapi doing its work.

   The kreung tam for gaeng som is simpler than most Thai curry pastes. No lemongrass, no galangal, no kaffir lime. That simplicity is the point. Every ingredient has to earn its place. If your paste doesn't smell intensely of shrimp paste and chili, pound harder.
2. 2

   Dissolve paste in water

   Bring the water to a boil in a medium pot. Spoon the kreung tam into the boiling water and stir to dissolve completely. The water will turn a warm orange, cloudy and fragrant. Let it simmer for 3 to 4 minutes so the paste releases its full flavor into the broth. This is not a coconut curry. There's no cream to crack, no oil to separate. You're building flavor in water alone, which means the paste has to be properly pounded to dissolve and infuse.

3. 3

   Cook the vegetables

   Add the daikon first. It's the densest and needs the most time. Simmer for 3 minutes. Then add the green beans and cabbage. Another 3 minutes. The vegetables should be cooked through but still have structure. Not crunchy, not collapsing. Thai sour curry vegetables have a specific texture: tender enough to absorb the broth, firm enough to hold their shape against rice.

   The vegetable selection for gaeng som is flexible. White radish, cabbage, green beans, morning glory, even cha-om omelet (acacia) are all traditional. Use what looks good at the market. The principle stays the same: vegetables that hold up in a sour broth.
4. 4

   Season with tamarind

   Add the strained tamarind water, fish sauce, and palm sugar. Stir once and taste. This is the moment that matters. Sour should hit first, that tangy tamarind pucker. Salty should follow, supporting the sour without overtaking it. Sweet should be barely perceptible, just enough to take the harsh edge off the tamarind. If the sour isn't loud enough, add more tamarind. If it's too sharp, a pinch more palm sugar. Gaeng som is a sour curry. Don't be afraid of the sour.

   Ajarn always said: the balance in gaeng som is deliberately unequal. Sour leads. If your gaeng som tastes like a balanced four-pillar dish, you haven't added enough tamarind. Push the sour. That's the identity of this curry.
5. 5

   Add the shrimp

   Add the shrimp to the simmering broth. They cook in 2 minutes. The moment they curl and turn pink, you're done. Pull the pot off the heat. Overcooked shrimp in a thin broth is unforgivable because there's nothing to mask the rubbery texture. Taste the broth one more time. Adjust. Ladle over jasmine rice in a bowl. The broth should pool around the rice, orange and fragrant, vegetables and pink shrimp scattered through it. That's gaeng som.

Chef Tips

• •Don't confuse Central Thai gaeng som with Southern Thai gaeng leuang. Gaeng leuang uses much more turmeric and is often fiercer in heat. Central gaeng som keeps the turmeric subtle, just enough for a warm golden-orange color. The identity is tamarind, not turmeric. If your curry looks bright yellow, you've crossed into Southern territory.
• •Tamarind quality matters enormously in this dish because it's the dominant flavor. Use wet tamarind paste (the block kind), not tamarind concentrate from a jar. Soak a walnut-sized piece in warm water, squeeze and strain. The pulp should taste bright and tart, not muddy or flat. Good makham piak is the difference between a gaeng som that sings and one that just sits there.
• •Some Bangkok home cooks add a handful of shrimp shells to the simmering broth before the vegetables, then strain them out. It gives the broth an extra layer of sweetness and body. My mother did this. It's not required, but if you have head-on shrimp, don't throw those shells away.
• •Gaeng som is traditionally served as part of a multi-dish Thai meal alongside something richer, like a stir-fry or a coconut curry. Its sourness and lightness cut through heavier dishes. That contrast is intentional. Thais don't eat one dish at a time. They eat systems of dishes that balance each other.

Advance Preparation

• •The kreung tam can be pounded up to a day ahead and stored in a sealed container in the refrigerator. The flavors will actually meld and intensify overnight.
• •Tamarind water can be prepared a day ahead and refrigerated.
• •Do not add the shrimp until you are ready to serve. They cook in 2 minutes and do not reheat well in a thin broth. Everything else can be simmered and held. The shrimp go in at the last moment.

Frequently Asked Questions

Nutrition Information

1 serving (about 425g)