I get quite a few hits on this exact search term. I’ve said in my own recipes that you can’t make a decent curry (or Chinese, for that matter) without oil and salt – so if you’re looking for a low-calorie, low-sodium meal without either of those you’re going to have to get used to it tasting a fair bit different to one that’s made the proper way if you start leaving these ingredients out.
Oil (or fat) has a number of functions depending on what it is that you’re cooking. Simple pan frying, for example, uses oil as a lubricant and you can get away with – say – frying an egg without oil (or with the tiniest amount) if you use a good non-stick pan. It will taste slightly different, but passable. Bacon and sausages contain their own fat and so the cooked taste isn’t affected as much if you “dry” fry them (though they might be a bit dry).
When deep-frying, though – and I’ll get to the curry question later – it is the fact that oil boils at a high temperature which is the really important factor. Consider making chips (or French fries). Your potatoes are cut up and ready to go. If you drop them in boiling water (which boils at 100°C), 10 minutes or so later you simply end up with boiled potatoes – still edible, but nothing like chips or fries. However, oils like Sunflower and Rapeseed Oil (Canola) can be heated to close to 200°C, which is almost at their smoke point. The smoke point is when the oil begins to (obviously) smoke and alter its chemical structure (i.e. to break down), and this influences the taste of whatever it is you’re cooking. It’s also why you can’t use the same oil too many times, as it degrades and begins to taste bad (it can also become toxic, as unsaturated fats break down into saturated ones and other chemicals are produced).
When you drop your chipped potatoes into the hot oil, the water in them starts to boil and escape as steam – this is why the pan appears to “boil”, even though it is just very hot. However, the high oil temperature also seals the outside of the chips so that the steam can’t easily escape, and this has the effect of cooking them from within. It also keeps them moist. Furthermore, the high temperature caramelises (or browns) the outside, and this gives the tasty golden brown colour you associate with chips and fries.
To cook chips or fries properly at home, the best technique is to double fry them – first, at about 140°C for about 5-6 minutes until the chips are nearly cooked (just before they start to brown – squeeze one to make sure it’s not hard), then remove them and heat the oil to about 180-190°C and fry them again until they are golden and crisp. A deep-fat fryer is best for this process so you can control the temperature more easily, but a pan and thermometer will work. Alternatively, instead of the first frying step, you can place the chips in boiling water for 6 minutes, drain them, plunge in cold water, drain, and then fry them at 180-190°C.
If you try to cook chips at a single temperature they either turn out soggy (lower temperatures) or burn on the outside but remain undercooked inside (higher temperatures).
But what has all this got to do with the curry question? Well, with curry, high temperatures are vital in order to develop the correct flavours. Curry is not supposed to be a boiled dish, and the only way to get the high temperature for the cooking process is with oil. If you just heat the dry pan and then add water-based ingredients like onions and tomatoes they will cook at around 100°C (and stick easily). Oil helps with lubrication and cooks them at close to 200°C – which is very different, and contributes dramatically to the all-important curry taste.
Furthermore, the essential oils in the spices which give the dish its flavour are soluble in the oil, but not always in water. So as well as allowing the “cooked” taste of the spices to develop, the oil allows those flavours to become properly dispersed for when they land on your tongue. I’m sure I once read that oil-based flavours interact with your taste buds differently to water-based ones, but it is certainly a fact that the mouth feel of oil alone has a very specific effect on your brain. A wet, water-based curry doesn’t feel right when compared with an oil-based one like you get from the takeaway.
Remember that you can drain off excess oil from a curry quite easily, and in any case you don’t have to eat it if it’s formed a pool on your plate. All you do is allow the curry to stand for a few minutes until the oil begins to separate, and either pour it off or use a large spoon to ladle it out (push the spoon down gently and collect the oil as it runs into the bowl). However, remember that curry is supposed to have oil in it, so leave some in.
How can I eliminate oil in my curry?
If you mean not use any at all, you cannot. An oil-free curry it isn’t a curry anymore, just something you might try to call “a curry”. The high temperature you can heat oil to, and the simple fact it is an oil in the first place, is what makes a curry taste the way it does. Watery curry doesn’t taste right, doesn’t look right, and doesn’t smell right.
Too much oil can simply be poured or spooned off, as I explained above.