Kaeng Som (Southern Thai Sour Curry Soup)

Asian Soups

Kaeng Som, also spelled Gaeng Som, is a classic spicy southern Thai sour curry soup. To be clear, it is not for the unadventurous. In the world of Southeast Asian soup recipes, this is one of the spiciest of them all. But if you’re up for a challenge, you’re in the right place, especially if you like set-your-mouth-on-fire-spicy (also sweating, watering eyes, and some serious nose drainage). This is perhaps not my most appealing introduction to a recipe.

Kaeng Som, a southern Thai sour curry soup

I know most Westerners don’t like spicy (or the thought of bodily fluids). But before you click away, know that this recipe can easily be adjusted to a mild or even non-spicy version (and sans the body fluids).

But traditionally, a Kaeng Som recipe is supposed to be a super spicy soup, at least the southern Thai version.

What is Kaeng Som?

Kaeng Som is sort of like the chicken soup of Thailand. It’s popular everywhere, including Thai street food, and hundreds of variations exist throughout the country. In Thai, “Kaeng” means curry, and “som” means sour.

At its core, it’s made from a simple curry paste of fragrant spices, vegetables and chiles which is dissolved in broth (or water). The paste is then simmered with shrimp or fish and other vegetables. There’s no coconut milk in this soup to balance the heat and that’s one of the reasons it’s spicy. The sourness comes from either tamarind or fresh lime juice.

The classic southern version is unique in three ways. First, it includes turmeric which gives the paste and the soup a yellowish-orange color. As a result, sometimes it’s called orange curry. In some places in southern Thailand, they also call it yellow curry. This is different from the more common Thai yellow curry coconut dish (called kaeng lueang in Thai), which is often simply listed as “yellow curry” on Thai menus (eating in Thailand can be very confusing) and which is typically sweeter and less spicy.

Second, it’s really spicy. And third, there’s little if any sugar.

Finally, the recipe is included in my cookbook, The Thai Soup Secret, which includes 40 restorative recipes for Thai soups, congees, and broths. Kaeng Som is without a doubt the spiciest recipe in the book!

Thai Soup Secret cover

Transform Your Health with Thailand’s #1 Superfood!

Includes 40 restorative recipes for broths, congees, and soups. All gluten and dairy-free!

More Thai Soup Recipes to Try

My Kaeng Som Experience

On my recent trip to Thailand, I learned that when you order a spicy Thai meal in southern Thailand, as a foreigner they mostly assume you’re a total wuss. The servers always ask you how spicy you want it and usually give three options — a little spicy, medium spicy, and Thai spicy.

“Thai spicy” means the real deal, in theory anyway. Because very few Westerners ask for things “Thai spicy,” sometimes they still err on the side of caution and tone it down.

But not always.

The first time I ordered Kaeng Som in southern Thailand it was the real deal… and then some.

Man did the sinuses flow. At the end of my meal, I’d used so many napkins that my table looked like it was in the path of a ticker-tap parade. I was sucking air for a good 15 minutes after the meal just to cool my mouth down.

But that doesn’t mean I didn’t enjoy it.  It was so good.  I don’t know why the combination of fiery chilies, sour lime, and earthy turmeric works so well but it just does.

Quick aside: did you know that eating spicy foods help cool your body down in hot weather?

Why You Should Make Your Own Thai Sour Curry Paste

If you’ve never made a homemade Thai curry paste before, this is the one to try. Why? Because unlike red, green, and other Thai pastes which can use dozens of ingredients (many of which are hard to find), Kaeng Som only uses a handful.

It was the first curry paste I tried making myself and the results were absolutely fantastic. I was surprised at how closely this resembled what I had in Thailand.

Here’s what you need…

Kaeng Som ingredients

Dried arbol chilies, a few shallots, a few cloves of garlic, and turmeric. I peeled that little piece of turmeric just see you could see the bright orange color.

You also need this…

shrimp paste

Shrimp paste.

The one pictured above is a Thai shrimp paste from my local Asian market. I don’t know if this is a great brand or not but there wasn’t any MSG or other chemical ingredients. The small 3-ounce-sized container was another benefit.

You can pick it up here on Amazon.

Most Asian supermarkets will have several options for shrimp paste.

Warning: if you live with people who may not be used to the smell of shrimp paste, prepare yourself for some comments along the lines of, “What the #%#& is that smell?!”

You will be harshly judged. Just a heads up.

Another heads up. Arbol chilies are really spicy!  You could also use fresh Thai bird’s eye chilies for even more heat. But if you want a mild version, you’ll have to use a milder chili. Try some large dried California chilies instead.

Finally, if you’re not ready to make your own paste, you can buy a pre-made paste. But unlike more common red and green curry pastes, pre-made sour curry paste is not as easy to find. My local Asian supermarket had this sour curry paste by Maesri.

Here’s how to make your own…

How to Make a Kaeng Som Curry Paste


Makes approximately 3/4 to 1 cup of paste

30 to 40 dried arbol chilies or 6 to 7 large dried California chilies
1-2 shallots
1-2 cloves garlic, optional
2-3 small 1-inch pieces of turmeric
1-2 teaspoons shrimp paste


1. First, soak the dried chilies. Pour some boiling water over them and let them soak until they soften, about 20-30 minutes.

2. Next, add about a 1/4 cup of the soaking water and about 30 of the dried arbol chilies, 1 shallot, 1 clove of garlic, 2 small 1-inch pieces of turmeric, and 1 teaspoon of the shrimp paste to a blender. Blend until it forms a paste.

3. Taste and add more of any ingredient, if desired.

That’s it!

fresh Thai sour curry paste

How to Make Kaeng Som

My version of Kaeng Som is fairly straightforward. I don’t like adding sugar, fish sauce, or tamarind juice, though many versions in Thailand include them, especially tamarind. Tamarind gives Kaeng Som a more tangy flavor than lime juice (it’s also a lot easier to use fresh lime juice).

I think the essence of the spicy and sour flavors gets a bit diluted when adding those ingredients.  By all means, add them if you want. In the end, it ALWAYS comes down to experimentation and personal preference.

Finally, traditional versions of Kaeng Som include Thai vegetables like bamboo shoots, Thai eggplants, morning glory, and green papaya. Those may be hard to find or just unfamiliar. Substitute any veggies you want. Thai vegetables that are just as common in the West include green beans, tomatoes, and cauliflower.

Most Kaeng Som recipes include steamed rice on the side which helps to temper the heat and to balance the flavors.

Kaeng Som Recipe (Southern Thai Sour Curry Soup)

Thai sour curries use a simple chili paste dissolved in broth (or water) and then simmered with fish or shrimp and vegetables and seasoned with generous amounts of lime juice.
Print Recipe Pin Recipe
CourseMain Course, Soup
Prep Time40 minutes
Cook Time20 minutes
Total Time1 hour
Servings4 people
AuthorCraig Fear


For the sour curry paste:

  • 30 to 40 Arbol chiles dried, or for a milder version sub 6 to 7 dried California chiles
  • 1 to 2 shallots diced
  • 1 to 2 cloves garlic optional
  • 2 to 3 small knobs turmeric fresh, about 1-inch per knob
  • 1 to 2 tsps shrimp paste

For the soup:

  • 4 cups fish stock or shrimp broth or just water
  • 1 to 4 TBSPs sour curry paste or store-bought Thai sour curry paste
  • 2 to 4 TBSPs lime juice
  • 1 pound shrimp or fish of your choice
  • 1 pound vegetables your choice of green beans, daikon radish, tomatoes, bamboo shoots, etc.


For the paste:

  • Soak the dried chilies. Pour some boiling water over them and let them soak until they soften, about 20-30 minutes.
  • Add about a 1/4 cup of the soaking water and about 30 of the dried arbol chilies, 1 shallot, 1 clove of garlic, 2 small 1 inch pieces of turmeric, and 1 teaspoon of the shrimp paste to a blender and blend until it forms a paste.
  • Taste and add more of any ingredient, to desired taste.

For the soup:

  • Bring broth or water to a simmer and add 1 TBSP of the paste at a time. Mix, stir and taste. Continue adding additional TBSPs to your preferred taste.  3 TBSPs is what I like but that's REALLY spicy!  You could even add more.
  • Add 2 TBSPs lime juice and then add more to desired taste.  If you’re cooking for more than yourself, you can leave out the lime juice and let each person add it to his/her individual bowl.
  • Add veggies and simmer a few minutes or until tender.
  • Add shrimp or fish and simmer for a few minutes or until cooked through.
  • Adjust flavors to desired taste with lime juice, fish sauce (or salt)or even sugar.
  • Serve with a side of steamed jasmine rice.
  • Enjoy!


Serving: 2cups (1 bowl) | Calories: 233kcal | Carbohydrates: 21g | Protein: 33g | Fat: 3g | Saturated Fat: 1g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 0.4g | Trans Fat: 0.01g | Cholesterol: 197mg | Sodium: 1013mg | Potassium: 865mg | Fiber: 6g | Sugar: 2g | Vitamin A: 6765IU | Vitamin C: 16mg | Calcium: 186mg | Iron: 3mg
Fearless Eating may receive commissions from purchases made through links in this article. As an Amazon Associate I earn from qualifying purchases. More info here.
Kaeng Som (Southern Thai Sour Curry Soup)

About the Author

Craig Fear is the creator of Fearless Eating and the author of three books, The 30-Day Heartburn Solution, Fearless Broths and Soups and The Thai Soup Secret. After years helping clients with digestive issues, Craig decided to pursue writing full-time. He intends to write many more books on broths and soups from around the world! Click here to learn more about Craig.