Kaeng Som – Thai Sour Fish Soup
Kaeng Som, or Thai Sour Fish Soup, is a golden yellow Thai fish soup that is tangy and full of umami, with a hint of spiciness. Enjoyed as an everyday dish in Thai households, it is usually cooked with fish and seafood.
This recipe is made completely from scratch, thus taking roughly about 1 hour to cook 850g of fish. However, this fish soup matures over time, deepening its flavour in the fridge. It’s perfect with some fluffy onion omelette and fluffy white rice.
Serves 6 – 8 adults.
What is Kaeng Som?
Kaeng Som is easily recognisable from its golden-yellow hue from the turmeric. The gravy is light and runny, almost like a non-creamy soup. Yet, the blended (or traditionally, pounded) curry paste made from scratch, thickens the bottom of the gravy, adding an intense sourness and umami-ness to the fish/ seafood.
There is a mild hint of spiciness, which goes very well with the tenderness of fish and the crunchiness of the al-dente vegetables. It is widely available in Thai restaurants and is often cooked in Thai households to enjoy with khai jiew (omelette) and rice. It is always cooked with fish or prawns, as the gravy is super fragrant and strong in flavour, it can mask the fishiness of seafood.
Water spinach, morning glory, or kangkung is another signature vegetable ingredient of this dish. Its ability to soak up the gravy adds to the intensity of flavours and a delicious contrast of crunchy texture when cooked just right.
Ingredients
- Guajillo Chilli
- Dried Chilli
- Tamarind Pulp
- Hot Water
- Sea bass fillet
- Red bird’s eye chilli
- Water
- Salt, to taste
- Sugar
- Cauliflower
- Water Spinach
- Turmeric
- Belacan, shrimp paste
- Garlic, peeled
- Shallots, peeled
Utensils
Tips
- Add the fish pieces only when the curry is boiling vigorously.
- Avoid moving the fish pieces after they are fully submerged in the curry until they are completely cooked.
- Water spinach cooks easily, so it will be just cooked with the residual heat.
- Ensure to watch the video to see exactly how I made it!
Storage Instructions
Leftovers can be kept in the fridge for about a week, in an airtight container. Any gravy leftover can also be used to cook the next batch of fish/ prawns and vegetables. Be sure to bring the gravy to a rolling boil, before submerging the newly marinated seafood completely without stirring, until fully cooked.
This recipe is also perfect for meal preps and it can be portioned out and frozen in the fridge for about 1 – 2 months. Do note that while the fish and gravy will retain their texture, the vegetables (water spinach and cauliflower) may change and become mushy as the ice crystals thaw out.
Similar Recipes
- Easy Tom Yum Seafood Soup Recipe
- Clear Tom Yum Fish Soup – Tom Som Pla
- Sweet Sour Spicy Fried Fish
- Fluffy Omelette
- Cauliflower Omelette Recipe
Kaeng Som
Equipment
- Blender
- Wok
- Turner
- Scissors
Ingredients
- 850 g fish fillets, sea bass
- 1/4 tbsp salt, to taste
- 1.5 L water
- 240 g cauliflower, cut into small pieces
- 330 g water spinach, kangkung, cleaned
Chilli
- 3 dried Guajillo chilli, soaked in hot water for 20 minutes
- 8 dried red chilli, soaked in hot water for 20 minutes
Tamarind Water
- 85 g tamarind pulp
- 300 ml water, hot water
Blended
- 30 g red birds' eyes chilli
- 20 g turmeric, fresh
- 40 g shrimp paste, belacan, less salty
- 50 g garlic
- 250 g shallots, peeled
- 300 ml water
Adjustments
- 275 ml tamarind water, optional, from the tamarind water
- 1/4 tbsp salt, optional
- 1.5 tbsp sugar, optional
- 1 tsp sugar, optional
- 1/4 tsp salt
Instructions
- Soak the dried Guajillo chilli and dried chilli with hot water for about 20 minutes.
- Soak the tamarind pulp in hot water for 5-10 minutes.
- Marinate the sea bass fish with salt in 2 parts.
- Squeeze and mix the tamarind pulp in the water until well combined. Strain the tamarind water and discard the seeds and pieces. Set it aside.
- Pull out the stems from all the chillies. Cut them into smaller pieces with a pair of scissors. Set them aside.
- Add red bird's eye chillies, turmeric, shrimp paste (belacan), garlic, shallots, and water into the blender and blend for 1 minute, or until very smooth. Set it aside.
- Heat a wok on the stove over medium heat. Add 1.5L water and all the blended curry paste. Scrape the residue into the wok. Pour about 200ml of tamarind water into the blender. Give it a swirl or two to wash the curry paste down. Pour it all into the wok and stir to mix. Cover the wok and let it boil for 20 minutes.
- Stir the curry paste. Taste and adjust. I added 200ml tamarind water, 1.5 tbsp salt and 1.5 tbsp sugar to the gravy. Stir until well-combined. Cover the wok and let it boil for another 10 minutes, or until the gravy has thickened slightly.
- Raise the heat to medium-high. Submerge the fish pieces in the curry gravy, starting with the head, and ending with the roe (if available). Cover and cook them for 2 minutes.
- Add the cauliflowers all around the wok. Cover the wok and let them cook for 2 minutes.
- Stir the curry. Taste and adjust. I added 1/4 tsp salt, 1 tsp of sugar and 75ml tamarind water. Stir to combine.
- Add washed and cleaned water spinach (kangkung), stirring to submerge them in the curry. Switch off the heat. Cover the wok and let it rest for 10-15 minutes.
- Dish it out and serve.
Video
Notes
- Add the fish pieces only when the curry is boiling vigorously.
- Avoid moving the fish pieces after they are fully submerged in the curry until they are completely cooked.
- Water spinach cooks easily, so it will be just cooked with the residual heat.
- Ensure to watch the video to see exactly how I made it!