Kaeng Tai Pla (แกงไตปลา)

The Curry Thailand Defends

แกงไตปลา is named for its engine: tai pla, the fermented guts of fish — the stomach, not the kidney the literal translation implies — salted and left to do its dark work in a bottle. Southerners also call it แกงพุงปลา, the fish-belly curry. The smell divides the country before the taste ever gets a vote, and in 2025 TasteAtlas ranked it ninth on its list of the world's 100 worst-rated foods — to which Thai social media answered with the #saveแกงไตปลา campaign and a national show of loyalty, as Kapook records.

The technique is a two-stage build. First the tai pla is boiled with aromatics and strained — Wongnai simmers it with shallots, galangal, lemongrass, kaffir leaves and tamarind; TrueID's selling version adds a rule of its own: leave the pot alone for five to ten minutes, do not stir, or the broth clouds. Then the fresh paste — dried chillies pounded first, peppercorns pounded separately and added last — goes into the broth with the vegetables, hard ones first, long beans dead last so they keep their crunch.

Mahidol's nutritionists describe the two schools: the classic is the clear version with no coconut milk — the one southerners actually favour — while the kathi version exists but adds fat to a curry already salty and hot enough to make the institute warn you to eat the solids and go easy on the broth. And TrueID's second recipe fries the whole idea down into kaeng tai pla haeng: the dry version, the same paste and tai pla water cooked with palm sugar and cashews until it is a sticky, spoonable concentrate.

The Recipe (home version, from Wongnai)

The selling batch (TrueID, แม่ซี): weights for about 2 litres — 15 g dried chillies, 30 g fresh jinda chillies, 30 g garlic, 25 g turmeric, 30 g shallots, 3 lemongrass stalks, 1 lime's zest, 1 spoon black pepper; tai pla 1 bottle boiled in 500 g water with 70 g fermented fish paste, galangal and kaffir leaves, then 1,500 ml water, 300 g pumpkin, 400 g aubergine, 300 g bamboo shoots, 100 g long beans, 2 grilled mackerel, palm sugar and tamarind to season. The academic bowl (Mahidol): no straining at all — the paste is dissolved straight into water, with 5 pieces of dried garcinia for sourness, southern greens and 40 fresh bird's eye chillies (see the disagreement below).

The Method

1. The paste. Pound the dried chillies until fine, then the kaffir zest, chopped lemongrass, turmeric, shallots and garlic. Pound the white and black peppercorns separately and add them last — Wongnai's order, and the difference shows in the nose.
2. The fish. Grill the mackerel until the skin chars and the flesh dries — Kapook's southern method grills pla-o over coconut husks until the meat is dry, so it holds together in the pot instead of collapsing to mush.
3. The tai pla water. Simmer the tai pla with shallots, galangal, lemongrass, kaffir leaves and tamarind, then strain and keep only the liquid. TrueID adds its rule: once the tai pla goes in, do not stir, or the broth turns cloudy.
4. The curry. Bring water to the boil, add the paste and shrimp paste, then the kaffir leaves and the strained tai pla broth. When it boils, add the bamboo shoots first, then the aubergine and the flaked fish.
5. The finish. Season with tamarind and a little palm sugar — Kapook's cooks adjust with a pinch of sugar or a squeeze of lime instead — then add the long beans last, boil once more and take off the heat. Serve with rice or khanom jeen and a plate of fresh vegetables; the beans must still crunch.

Where Thai Sources Disagree

How Western Versions Get It Wrong

• Substituting fish sauce for tai pla. A splash of fish sauce cannot stand in for fermented fish innards. The funk is the dish — replacing it produces a perfectly pleasant chilli soup that is not kaeng tai pla.
• Adding coconut milk by default. The southern classic is the clear version; Mahidol is explicit that the no-coconut-milk curry is the one southerners actually prefer. Coconut milk turns it into the minority variant.
• Boiling the vegetables soft. Thai method keeps the vegetables just-cooked — long beans go in last and the pot comes off the heat while they still crunch. A western-style long simmer turns the curry to vegetable sludge.
• Skipping the strain. The strained tai pla broth is what separates a clear, deep curry from a murky one — and the no-stirring rule while it boils is the detail that keeps it that way.
• Curry powder instead of the fresh paste. The paste is pounded fresh — dried chillies, turmeric, kaffir zest, peppercorns. Curry powder gives none of the brightness and all of the dust.

UK Ingredient Notes

• Tai pla (ไตปลา): bottled and shelf-stable — Thai grocers and online Thai supermarkets carry it; the label says tai pla or "fermented fish innards".
• Pla thoo (short mackerel): frozen at Thai grocers; fresh or smoked mackerel from any UK supermarket works as a stand-in.
• Kaffir limes and zest: fresh fruit at Thai grocers when in season; frozen kaffir lime leaves year-round.
• Fresh turmeric: now standard in UK supermarkets and Thai grocers.
• Som paen leaves and dried garcinia are not exported — Mahidol's bowl is for the trip south; young spinach or pea shoots and tamarind water get you most of the way.

Sources

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