A lot of curry recipes tell you to keep going until the oil separates, but for me this point never comes. I've tried putting more oil / butter in to start with, but no joy. I've also tried turning up the heat - same. Can anyone tell me where the oil comes from, and what causes it to be released?

[Edit following comment]

For example, I just made one as follows:

Coat 130g king prawns in a mixture of 1/2 tsp turmeric, 1 tsp chili powder, pinch salt and set aside

Fry half lg onion and a clove of garlic (chopped) in a generous amount of butter until onion translucent

Add 1/2 tsp cumin, 1/2 tsp coriander and stir in

Add 80g tomato paste, 1/2 cup water and leave to simmer for 5 - 10 mins

Add prawns and simmer until cooked through

When the prawns were done, the sauce was at about the right consistency but there was no sign of the oil separating out. I'd had the frying pan at a temperature where it would stop bubbling if stirred.

I left it for another few minutes but the prawns were getting overdone and so was the rice I had on the other ring, so I called time on it.


  • Basically you need to reduce the water until there's pretty much only oil & solids left - but we need more detail of what your recipe is to give any more detail.
    – Tetsujin
    Commented Dec 7, 2019 at 14:30
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    Are you improving the recipe by adding secret ingredients? It's possible that something is acting as an emulsifier and binding the oil to the non-oil ingredients. (E.g. the way that a small amount of egg yolk allows oil and vinegar to mix and become mayonnaise.) Commented Dec 7, 2019 at 14:46
  • 1
    I'd add to this that "generous" amounts of oil or butter in Indian cooking tends to be an awful lot.
    – GdD
    Commented Dec 7, 2019 at 17:45
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    I believe this is meant to occur in the early stages, when cooking the spices, onions, tomatoes, etc. From what I've seen it should happen before you add the meat - especially prawns. In recipes that include this direction, I don't see oil separating really, but it seems to pull away from the pan at that point, because (as Tetsujin says) the water is mostly gone, so oil, however little, is on the surface. Commented Dec 7, 2019 at 19:16

1 Answer 1


Sounds like the butter, tomato paste and water are combining into an emulsion as Ray suggested. Many recipes online for British Indian Recipe curries (BIR) rely on this method to get the oil to separate. This also happens in other dishes like stews and casseroles etc.

In the BIR scenario, a base gravy (which is a blended mixture of spices, onions, water, oil and tomatoes) is kept warm and added to the garlic paste, spices etc. which is already frying in a large amount of oil. As the base gravy starts to reduce and the water evaporates, the solids congeal and the oil starts to separate out. This also occurs when a blended mixture of tomato puree and water is added to the very hot pan, and an orangey-red flavoured oil is the result.

I have achieved this using ghee, vegetable oil, coconut oil or rapeseed oil. It sounds to me that the butter itself is the culprit here, it could possibly be the milk solids are helping everything to bind together.

I would try without butter, heat some oil up and fry some garlic paste (garlic blended with oil or water) until fragrant. With the heat still on high, add your spices, stir, and add about a tablespoon of tomato puree which has already been blended with a tablespoon of water, and stir vigorously. The oil should start coming out from the spices and the garlic (which will be thicker), and the seperated oil a red-brown colour depending on the spices used.

I've seen the same result happen when I have fried onions, garlic in a large amount of oil, added tinned plum tomatoes, fried for a short time, then stirred well, reduced to a simmer and covered. After about 10 minutes or so, the oil separates out.

The key to this process seems to be a) Lots of oil b) High initial temperature and c) time.

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