Tom Saap, Tom Saap Kraduk Moo, Isan Hot-and-Sour Soup
This thai spicy pork rib soup recipe is tom saap, the hot-and-sour soup of northeastern Thailand: pork spare ribs simmered for over an hour with lemongrass, galangal and kaffir lime leaves, then sharpened at the last minute with tamarind, lime juice, fish sauce and two kinds of chilli, plus a spoonful of nutty roasted rice powder. It is clear and bright, never creamy — a world away from tom yum. One serving is about 500 g.
Tom saap comes from Isan, the northeastern region of Thailand, where saap means delicious in the local Lao dialect and tom means to boil. It began as a resourceful country soup that tenderised tough cuts — beef, offal or pork — with long simmering, then brightened them with lemongrass, galangal, kaffir lime leaves and roasted chilli. Street vendors later made the pork-rib version, tom saap kraduk moo, the most popular, and the same broth piled over pork spine became leng saap, the famous tower of bones sold at Bangkok night markets. Unlike tom yum, tom saap never uses coconut milk — its broth stays clear, sour and hot.
Pairs well with: Steamed jasmine rice, sticky rice, green papaya salad and a cold lime soda
Provenance
Thailand
Isan Street Classic
East & South Asia
Time Dedication
1h 50m
20m prep • 90m cook
Batch Yield
4 Servings
460 kcal per serving
1 serving ≈ 500 g
Technical Skill
Intermediate
Medium (Long Simmer)
Meal Timing & Digestive Fit
Breakfast
Not Advised
Lunch
Prime Metabolic Fit
Dinner
Ideal Hearty Main
Snack & Tea
Inappropriate
Isan Street Classic
Photo: Aaaatu, CC BY-SA 4.0, via Wikimedia Commons
The Heritage Formulary
Estimated cost: Low — about $3–4 per serving at home (USD)
Good tom saap is clear and bright, sharply sour first, salty second and hot third — never creamy or sweet.
Execution Methodology & Culinary Technique
Prep Stage: Blanch the Ribs and Ready the Herbs
20 Mins • Hands-On
Put the ribs in a pot, cover with cold water and bring to a rolling boil, 100°C (212°F), for 5 minutes, then drain and rinse them — this keeps the broth clear instead of cloudy. Meanwhile, bruise the lemongrass, slice the galangal into coins, tear the kaffir lime leaves, halve the shallots and crush the garlic. Toast the dried chillies in a dry pan for 1 minute until fragrant, then crush them coarsely. Whisk the tamarind paste with a little warm water until smooth.
Maestro Tip: Blanching the ribs is the difference between a bright, clear tom saap and a murky one — never skip it.
8 Mins • Hob Boiling water, 100°C (212°F)
Put the rib pieces in a large pot, cover with cold water and bring to a rolling boil. Boil for 5 minutes, skimming off the grey foam, then drain the ribs and rinse them under running water. Wipe the pot clean.
Skim the foam as it rises — that is what clouds the broth.
Done when: Ribs clean, foam gone, water clear.
75 Mins • Hob Gentle simmer, about 95°C (200°F)
Return the ribs to the pot with the 1.5 litres of fresh water, lemongrass, galangal, kaffir lime leaves, shallots and garlic. Bring to a gentle simmer — small bubbles, never a rolling boil — cover partly and cook for 75 minutes, skimming now and then, until the meat is tender and nearly falling off the bone.
A rolling boil makes the broth cloudy and the meat tough; keep it at a lazy simmer.
Done when: Meat tender, broth clear and fragrant.
10 Mins • Hob Simmer, about 95°C (200°F)
Stir in the tamarind paste, fish sauce, sugar and salt, then add the toasted dried chillies and the bruised bird's eye chillies. Simmer for 5 minutes, then taste: it should be sharply sour first, salty second, and hot third. Adjust with a little more lime, fish sauce or chilli to your taste.
Season in this order — sour, salty, then hot — so each flavour stays distinct.
Done when: Broth bright, sour, salty and hot in that order.
7 Mins • Hob Simmer, about 95°C (200°F)
Add the torn oyster mushrooms and simmer for 5 minutes until just cooked. Take the pot off the heat, stir in the lime juice and sprinkle over the roasted rice powder, sawtooth coriander and spring onion. The lime goes in last so its fresh scent survives.
Lime juice added while the soup boils loses its brightness — always add it off the heat.
Done when: Mushrooms tender, herbs bright, broth steaming.
2 Mins • Serving Serve hot, about 80°C (175°F)
Ladle the ribs and broth into deep bowls, making sure each bowl gets meat, mushrooms and plenty of broth, and serve immediately with steamed rice on the side.
Tom saap waits for no one — the herbs fade fast once the soup cools.
Done when: Steaming bowls, meat falling off the bone.
Finishing Touches & Plating
Eat tom saap the moment it is served, while the broth is steaming and the herbs are still bright. Spoon rice into the broth or eat it on the side — either way, the sour-hot broth is the point.
Nutritional Physiology & Benefits
Energy
460
kcal / serving
Protein
24g
Complete AA
Carbs
28g
Complex
Fats
29g
Healthy
| Energy | 460 kcal |
| Protein | 24 g |
| Carbohydrates | 28 g |
| Fat | 29 g |
| Fibre | 4.0 g |
| Sugar | 10.8 g |
| Sodium | 970 mg |
| Energy | 92 kcal |
| Protein | 4.8 g |
| Carbohydrates | 5.6 g |
| Fat | 5.8 g |
| Fibre | 0.8 g |
| Sugar | 2.2 g |
| Sodium | 194 mg |
Nutrition values are estimated — calculated from USDA FoodData Central values for the listed ingredients.
Vitamins & minerals: Vitamin C (lime and chillies), vitamin B6 and B12 (pork), iron and zinc (pork ribs), vitamin D (mushrooms). Nutrition values are estimated.
Protein That Fills You Up
About 24 g of protein per serving from the pork ribs makes this a substantial lunch that keeps you full for hours.
Fresh Herbs, Real Flavour
Lemongrass, galangal, lime leaves and chillies bring vitamin C and aromatic oils with no cream, coconut milk or frying.
Light, Clear Broth
The broth is water-based and clear, so the soup feels light and refreshing even though the ribs themselves are rich.
Food Pairings
To optimize nutrient absorption and elevate the sensory depth, pair with these authentic accompaniments:
Sides
Steamed Jasmine Rice
Plain jasmine rice soaks up the sour-hot broth and tames the chilli, bite by bite.
Sticky Rice
In Isan, sticky rice is the traditional partner — roll a small ball, dip it in the broth, and eat it with the meat.
Vegetables
Green Papaya Salad
Som tam's sour crunch echoes the soup's flavours while adding fresh, raw vegetables to the meal.
Drinks
Cold Lime Soda
A cold, lightly sweet lime soda cools the chilli heat and matches the soup's citrus notes.
Full Menus
Isan Table
Tom saap, sticky rice, som tam and grilled chicken make a classic Isan spread — sour, hot, smoky and fresh at once.
Complete menu
Start with tom saap and sticky rice, add green papaya salad and grilled chicken, and finish with a cold lime soda — a classic Isan table.
Digestive Guardrails
To prevent digestive distress, sluggishness, or palate clash, avoid pairing the dish with these elements:
Undercooked Pork Ribs
Pork must be cooked through until the meat is tender and the juices run clear — undercooked pork can carry harmful bacteria and parasites. Simmer the full 75 minutes and check the meat is tender. This is general food-safety information, not medical advice.
Too Much Fish Sauce and Salt
Fish sauce is very salty, so season a little at a time and taste as you go. A bowl of tom saap is already high in sodium — do not add extra fish sauce at the table if you watch your salt.
Very Hot Chillies for Sensitive Stomachs
Bird's eye chillies and dried chillies make this soup genuinely hot, and too much can irritate a sensitive stomach. Start with half the chillies and add more to your own bowl.
General information only, not medical advice — consult a doctor for personal dietary decisions.
Who Should Eat It
Health Conditions — Adjust or Avoid
If you have a medical condition, consult your doctor before changing your diet.
Storage & Use
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