Heat Oil Until It Smokes

[Shel_B]

Recently I've been thinking about that instruction which appears in numerous recipes. It seems like a counter-productive idea as, once oil starts to smoke, it starts breaking down, yes? Is there any benefit to heating cooking oil to the smoke point?

[dcarch]

The purpose is not to have all the oil smoke.

The purpose is to heat up the cooking vessel to the hotest possible temperature to retain maximumn heat.

When the oil starts to smoke that means you should not go further heating up the oil, you should start cooking.

dcarch

[Jenni]

Any particular kind of oil? It is common for recipes to instruct you to heat mustard oil up to smoke point as this turns the oil from pungent to something more docile and sweetish.

[Shel_B]

Any particular kind of oil? It is common for recipes to instruct you to heat mustard oil up to smoke point as this turns the oil from pungent to something more docile and sweetish.

I've seen the instruction for various kinds of oil, although not mustard oil. I see it frequently for olive oil.

[Norm Matthews]

Oil does start to break down when it starts to smoke but when you cook like that, you are sautéing or pan frying and not going to use the oil again, so it's not going to make a difference, especially if you start cooking immediately at that point. Those instructions expect that you will be using common vegetable oils that smoke right around 400º. Oil used for deep frying should not be heated that hot, especially if you are planning to use it again a few times. Non stick pans usually don't hold up very well over the long term if they are heated that much. Cast iron will take longer to heat up but hold the heat longer. Tri clan steel will heat up quickly and care should be taken that it does not over-heat the oil and itself.

highly flavored oils break down and loose distinctive flavor characteristics when used at the smoke point so consider using relatively neutral flavored oils for this technique. extra virgin olive oil is expensive for using with this method. Use regular olive oil if you use olive oil at all.

Edited January 18, 2012 by Norm Matthews (log)

[threestars]

Well I think when frying anything, when the pan/oil reached its maximum heat... the food you want to fry, for example is fish, won't stick on the pan because the oil is on its maximum heat. That's just an opinion. Not sure if its true.

[Alcuin]

The smoke is just a signal that it's time to put the food in to saute. You want the fat just this side of the smoke point because that tells you it's as hot as can be. You want it this hot because when you add the food, the temperature of the pan will decrease and you want it to return to temp as fast as possible. This is good because it does help keep the food from sticking plus it will ensure that you are actually sauteing the food, not steaming it which is what would be happening over lower heat (like when you sweat onions in fat over lower heat, which is not sauteing and which you don't want to be doing when you should be sauteing).

[Msk]

Though I believe its more about getting the pan hot enough to cook, before the cold ingredients are put in (and lower the pan temp as stated above.) I believe the oil breakdown also contributtes to maaillard reactions. Its why clean oil doesn brown french fries well on the first batch, if I recall correctly.

Mike

[Norm Matthews]

That is an interesting theory about fries but I am not sure it is entirely correct. When I do potatoes in deep oil, they don't brown on the first time in even if the oil has been used before. Fries are fried at a lower temperature to cook them through, then on the second time, the heat is raised to brown them on the outside while the inside stays creamy. Every time you use oil for frying, the smoke point drops somewhat. Once it starts smoking at cooking temperature, it is time to change the oil.

When one is sautéing, as Alcuin states, it helps to release what is cooking and little oil is used so that when done, the oil is discarded and not used again so smoke isn't an issue. Some oil may be retained in the pan while it's deglazed for making a sauce though.

The thing about smoking oil is that it has just started to break down and if you keep it, it is open for oxidation which is when the oil is no longer safe or good to use anymore.

[djyee100]

A professional cook once told me to put a little old oil in with fresh oil when frying, so that the food would fry better. He said the soaps in the old oil would aid the frying process. At the time we were frying batches and batches of something. So when the oil in the pan was exhausted, I kept a little of the old oil for the next batch, instead of dumping it and starting again with all fresh oil.

As to why soaps in old oil help with frying, Russ Parsons' book has an explanation. Here, on Googlebooks, page 14:

http://books.google.com/books?id=E0S45qEjW40C&pg=PA14&lpg=PA14&dq=using+old+oil+with+fresh+oil+when+frying+soaps+in+oil&source=bl&ots=MAI9sEs8OZ&sig=MNm5v0ml9vgLQCCtkSdnwExT9Iw&hl=en&sa=X&ei=YnQXT8CRE6jjiALLuMm5Dw&ved=0CB4Q6AEwAA#v=onepage&q=using%20old%20oil%20with%20fresh%20oil%20when%20frying%20soaps%20in%20oil&f=false

[Msk]

That is an interesting theory about fries but I am not sure it is entirely correct. When I do potatoes in deep oil, they don't brown on the first time in even if the oil has been used before. Fries are fried at a lower temperature to cook them through, then on the second time, the heat is raised to brown them on the outside while the inside stays creamy. Every time you use oil for frying, the smoke point drops somewhat. Once it starts smoking at cooking temperature, it is time to change the oil.

When one is sautéing, as Alcuin states, it helps to release what is cooking and little oil is used so that when done, the oil is discarded and not used again so smoke isn't an issue. Some oil may be retained in the pan while it's deglazed for making a sauce though.

The thing about smoking oil is that it has just started to break down and if you keep it, it is open for oxidation which is when the oil is no longer safe or good to use anymore.

There is alot more behind using oil than just releasing food, though that may have been the original goal. MC goes into detail about different such things, but I don't have mine handy to quote. At a minimum, oil is significantly fore efficient at delivering heat to the food, and broken down oil does accelerate brownin as the by products of the breakdown of oil allow penetration of the vapor barrier that forms when cooking. That idea was from Russ Parsons "How to Read a French Fry." Not me.

[dcarch]

There are many recipes which call for pouring very hot oil on food, after the food is cooked.

dcarch

[Norm Matthews]

The link posted by djyee100 about keeping some old oil for better browning was very interesting and informative. When I use oil for deep frying, I let it cool and settle out, pour off the clear and save it for reuse, then refresh it with new oil so I use some old oil about 70% or more of the time. I thought I was just being thrifty but apparently it is more efficient too. Still when I do french fries, I don't get a good crisp brown until the batch goes in for a second time at about 30 degrees hotter than the first time. That is why I wonder if using new oil is really the reason fries are 'double dipped' so they can brown on the second time in.

[djyee100]

...Still when I do french fries, I don't get a good crisp brown until the batch goes in for a second time at about 30 degrees hotter than the first time. That is why I wonder if using new oil is really the reason fries are 'double dipped' so they can brown on the second time in.

My french fries don't brown well until the second frying, either, if I'm using the double-dip method. I'm guessing that has more to do with the level of moisture in the potatoes rather than the quality of the oil. The first frying dries them out some. Fritters can be stubborn about browning, I suspect for the same reason.

[Norm Matthews]

My theory ( this is home cooking in cast iron chicken fryer on an electric stove) is that for the first fry, the hand cut raw potatoes go in at about 350º, the temperature drops to 330º or so and raise slowly while they cook through in seven or eight minutes. On the second fry the warm pre-cooked potatoes goes in the oil at the higher temp. of around 370-380º and the temp. does not drop significantly and they get fried brown and crisp on the outside in a minute or less. I suppose less water, oil on the surface of the potato, warmer temperature of the potatoes and higher temperature of the oil all combine to finish cooking the potatoes so they are soft and done inside and crispy outside. They'd burn or be raw in the middle if only cooked once at the higher temperature.

edit:From the link mentioned above, all this apparently happens easier if the oil has been 'tempered' with some old oil however.

Edited January 19, 2012 by Norm Matthews (log)