Tom Klong (ต้มโคล้ง)

The Broth Built on Smoke

ต้มโคล้ง looks like tom yum and sounds like tom yum, and Aroifin says exactly that — but it leans salty and sour where tom yum leans sour and fragrant, and its whole character comes from what goes in the pot before the water: dried fish, crispy fish or grilled fish, plus herbs that have met fire. Every source roasts something. It is the difference between the two soups, and it is non-negotiable.

Pim's kitchen puts the comparison in a box: tom yum uses fresh herbs, klong uses roasted ones; tom yum sours with lime, klong with tamarind; tom yum's heat is fresh chillies and nam prik pao, klong's is roasted dried chillies plus crushed fresh ones; tom yum simmers fresh prawns and squid, klong simmers grilled or fried fish. Swap any one of those and you have made the other soup.

The tradition is older and stricter than the home versions. Aroifin's notes: the original broth was sour from tamarind, salty from salt — not fish sauce — and sweet only from the fish and the roasted shallots. No sugar, ever. Modern kitchens swapped in lime and fish sauce; the classics were barramundi, salted fish and tilapia. And the Pantip poster, planning a pot from two market-grilled fish bought at 60 baht each, wanted the old finishing touch — young tamarind leaves — but the tamarind trees hadn't sprouted, so lime at the end had to do. The soup survives because it bends.

The Recipe (home version, from ครัวบ้านพิม)

The snakehead version (Aroifin): 1 grilled snakehead, 3 tbsp fish sauce, 1 tsp salt, 2 ladles tamarind water, 1 cup roasted shallots, 1 cup sliced galangal, 1 small cup bruised lemongrass, 4–5 torn kaffir lime leaves, roasted dried chillies to taste, 1 small cup holy basil to finish — one serving, 449 kcal. The dried-fish version (Cookpad): 6 small dried fish, everything grilled first, a tom yum stock cube, 450 ml water, 1 tbsp tamarind water, ½ tbsp lime juice, 1½ tbsp fish sauce, ⅓ tsp palm sugar. The long simmer (Pantip): whole market-grilled fish simmered 25–30 minutes on medium-low with flower salt, then lime squeezed in last, off the heat.

The Method

1. The prep. Chop the grilled catfish into 5–6 big pieces (no head). Slice the lemongrass short, the galangal into ½-cm slices, tear the kaffir lime leaves, halve and bruise the shallots, quarter the tomato.
2. The roast. Dry-roast the galangal, lemongrass, shallots and tomato in a pan until fragrant. This is the move that makes it tom klong and not tom yum.
3. The broth. Stock into the pot with the galangal, lemongrass and shallots over medium heat. Once boiling, add the tamarind, salt and fish sauce, and simmer until the herbs smell right.
4. The fish. Add the catfish, then the tomato, mushrooms and crushed bird's eye chillies. Once it boils, taste — sour leading, salty following, not too hot — and fix whatever is missing.
5. The warning. Don't boil long once the fish is in; grilled fish falls apart. Pim's exact rule.
6. The finish. Kaffir lime leaves and coriander go in last; one more boil, off the heat, and it's ready.

Where Thai Sources Disagree

How Western Versions Get It Wrong

• Making "tom yum with fish" and calling it klong. Fresh aromatics, lime-only sour, nam prik pao — Pim's own comparison says that is tom yum. The roast, the tamarind and the grilled fish are the dish.
• Poaching fresh raw fish in the broth. Every source starts from grilled, dried or crispy fish. The smoke is the soup; a fresh salmon fillet makes a different dish entirely.
• "Balancing" it with sugar. Aroifin: the traditional broth has no sugar — the sweetness comes from the fish and roasted shallots. Western renditions that sweeten it are inventing a tom yum habit for a soup that never had one.
• Jarred tom yum paste or coconut milk. None of the five sources uses a paste, a cube of curry, or any coconut. Tom klong is a clear, herbal, smoky broth.
• Slicing the kaffir lime leaves in early. Aroifin's warning: tear them by hand — slicing makes the soup bitter — and Pim adds them at the end. Early, shredded kaffir is the quickest way to ruin it.
• Skipping the roast. "Every herb must be roasted until fragrant, or the broth won't be right" — Pantip's rule, and every other source's practice. Steaming the herbs fresh is tom yum.

UK Ingredient Notes

• The fish: Thai market grilled catfish doesn't exist here — hot-smoked mackerel or trout works beautifully, or grill fresh mackerel or sardines yourself. Aroifin's rule: any firm fish that has met fire.
• Dried fish for the Cookpad version: Asian grocers stock dried anchovy and small dried snapper.
• Galangal: fresh from Thai grocers; frozen in a pinch (the roast recovers the aroma).
• Kaffir lime leaves: fresh or frozen at Thai grocers.
• Tamarind: block pulp from Thai or Asian grocers — soak in warm water and squeeze; seedless paste is quicker.
• Dried whole chillies: Thai grocers; dry-roast in a pan until crisp, then crush coarsely.
• Bird's eye chillies: mainstream supermarkets.
• Holy basil (kaprao) for the Aroifin finish: Thai grocers — sweet basil is a poor stand-in, coriander is the safer substitute.
• Flower salt: any good flaky sea salt stands in for Pantip's ดอกเกลือ.

Sources

This recipe is translated from the following Thai-language sources. Where they disagree, we've said so.