Why Your Curry Sauce Won’t Thicken (And How Curry Houses Get That Glossy Texture)
If your curry sauce stays watery no matter how long you simmer it, the issue isn’t a missing thickener — it’s technique. Indian restaurants don’t rely on cornflour, cream or paste. They build thickness by controlling onions, moisture and fat.
Quick Answer
Curry sauce won’t thicken because excess water isn’t driven off, onions are cooked incorrectly, or oil never separates and emulsifies with the spices. Restaurants achieve thick, glossy sauces by slow onion breakdown, moisture reduction and proper oil separation.
1) Your onions haven’t broken down properly
Onions are the primary thickener in most curry sauces. If they’re undercooked, rushed or burnt, they never release the sugars and starches that give body.
2) Too much water too early
Adding water before the base has developed flavour dilutes everything. Restaurants reduce liquid first, then add measured amounts later.
3) No oil separation
Oil rising to the surface isn’t a mistake — it’s a signal that the sauce has emulsified correctly. Without this step, sauces stay thin and dull.
- Cook onions until soft and translucent.
- Reduce moisture before adding liquid.
- Fry spices in oil properly.
- Allow oil to separate.
- Finish with controlled liquid.
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