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Smoke Point.

post #1 of 15
Thread Starter 
I have a bunch of questions about what the smoke point is. (I attended a community education cooking class tonight and the topic came up briefly.)

As I understand it, the smoke point is the temperature at which the oil in the pan starts to smoke. And that, once the oil reaches that point, the oil can break down, reducing its effectiveness for cooking and that, actually, it can also produce compounds that can be very unhealthy to ingest.

So, if that is true, is it the objective to put food (say, a steak for example), into the hot fry pan before the oil reaches the smoke point, or do you wait until it actually does reach the smoke point? If you should put the food in before it reaches the smoke point - to avoid unhealthy compounds - how do you know when to put the food in?

Possibly unrelated but, when I've seen chefs cooking, there is often lots of smoke. Is this smoke from the oil, or is it smoke from the food itself?
post #2 of 15
As soon as the oil starts smoking, you put your steak in. The oil won't burn that quick anyway.

The smoke you see when chefs are cooking is the juices evaporating from the food, I think :).
post #3 of 15
there are some techniques / recipes / directions which call for starting with a really hot pan. I've heard the "heat it up until it just starts to smoke" for any number of things.

realize, theres several hundred degrees difference in smoke points - so.... take note of what oil is being used when the recipe/chef recommends that approach. and plunking some cold in the pan will very quickly knock the temperature down.

smoke generated during cooking is not from the oil - if it is, the dish is gonna taste real bad - per your initial post, burned oil = bad taste, etc.... but from the (typically) meat starting to sear/brown/char - which will happen way below the smoke point of most vegetable based oils.
post #4 of 15
Thread Starter 
So what is the purpose of waiting for the smoke point before placing the steak in the fry pan? (Especially, as you mentioned, the smoke points can vary by a lot, depending on the oil used.)
post #5 of 15
......So what is the purpose of waiting for the smoke point before placing the steak in the fry pan?

it's a visual clue that there pan is really cotton picking HOT!

required state of affairs for some dishes example: steak Pittsburgh style

......depending on the oil used.)
ayup. hence the notation: know what oil is in use.

if I'm going to do steak Pittsburgh style, I'm reaching for safflower oil - because I know it will take more heat and want the mostest heat I can get.
post #6 of 15
When very hot oil is used you get desired flavor effects on meat, however the formation of unhealthy compounds also increases. This is no problem as long as you have a balanced diet (you know, lots of fruits, vegetables and whole grains) with little fried foods
post #7 of 15
post #8 of 15
When cooking oil starts to smoke, it means that it's starting to break down. The more it breaks down, the less effective it is as a cooking agent; and the worse it begins to taste. Of special interest to you as you cook for your family, oil which has been overheated has adverse health consequences.

The smoke point itself, is not a magic place where before everything was hunky-dory, but as you hit it all of a sudden tons of bad things start, and the whole world goes to kablooey. Rather, things start to happen as the oil approaches the smoke point, and get worse the farther beyond the smoke point and the longer the higher temperatures are held. It's more accurate to think of the danger zone for oil being a range.

In fact, you can see the oil start to darken before it goes dark. Oil which has been reused several times will start to darken even if it's kept within the safe temperature range, and this is a sign the oil is breaking down into its components of fats, water, and "other stuff" (chemical term). Darkening and smoking are both signs of separation and degradation -- and result from the action of heat on the fats (lipids, lipoproteins).

There are assorted health dangers associated both with the fumes and the oil. The oil and food cooked in it is bad enough, but the fumes are particularly bad for you. They are supposedly quite carcinogenic, and an otherwise healthy diet is not a remedy.

Some restaurant kitchens use the smoke point as short hand for "NOW." A small amount of oil in a very hot pan over a very high flame will hit the SP pretty quickly, and getting the food in right away will reduce the heat to where things won't taste bad -- and most of the bad stuff hasn't happened anyway. But restaurant kitchens use flame you can't get on a residential stove and work at a level of timing and teamwork you can't imagine until you've done it. This is one of several restaurant practices you shouldn't imitate.

Even though it's ingrained in a lot of restaurant kitchens, it's bad technique. Better restaurants encourage cooks to start just below the smoke point and not use the SP as a reference. You don't live in a restaurant, and the smoke point is something you should experience only by accident. If you smoke the oil, throw it out and start over.

If you're using a small amount of oil, as for a saute or a sear, preheat the pan empty over your best guess as to what it will be when you cook -- usually medium high -- for about two minutes. Remove the pan from the flame, and while you're holding it off the flame add your oil (this keeps the oil from smoking right off the bat), swirl the oil in the pan (if it's hot the oil will run like water, if it runs slow it's going to need some more heat), and return the pan to the fire. Make sure the entire bottom of the pan is covered before checking for shimmer. If the air right above the oil looks like it's shimmering, the oil is hot and you may add the food. (The shimmer point for everything but butter is about 20 degF below the smoke point.)

If you're using a low smoke point fat like butter or extra virgin olive oil, reduce the heat to medium. Butter will smell like hazel nuts before it starts getting bitter -- that's because the milk solids toast before they burn.

Remember, if anything starts to smell bad -- toss it. It's not worth fooling around with it -- especially in your situation.

You ask the darmmdest questions, they go deep and require a lot of explanation. I'm never sure whether to pat your back or wring your neck.

post #9 of 15
I've heard a number of folks say that adding a bit of oil to butter will increase the smoke point. The milk solids in butter that are the first to start to burn will start to burn at the same temperature whether or not there is any oil present. The addition of oil just makes the reaction take a bit longer.

Having said that I still use a mix of butter and oil for lots of things as I feel a butter and oil mix just makes it taste better than oil alone.

Food nourishes my body.  Cooking nourishes my soul.
Food nourishes my body.  Cooking nourishes my soul.
post #10 of 15
Thread Starter 
Hi BDL, Thanks for your great explanation. I didn't even think about the unhealthy smoke aspect of the smoke point. And it was very interesting what you said about how a restaurant operates versus how a home kitchen should operate.

One thing - if different oils have very much different smoke points, then are you supposed to match up the oil with the particular food you are cooking? Or, if you simply want to be able to use as high a temperature as possible, why wouldn't you just use an oil that has a smoke point of 1,000 degrees?

The reason I am still puzzled is that it doesn't appear that we're seeking a specific temperature for a specific type of steak but that we just want to get to, or we want to approach, the smoke point.

Also, one small incidental question - what is the "shimmer point?

Thanks again for your great answers, and thanks for the compliment on my question.:lips::lips:
post #11 of 15
Thread Starter 
BDL - You can strangle if you wish - I would understand.:lips:

Seriously, I think this bulletin board is terrific, and I am thankful that everyone has given me so much help and that you don't need to be an expert chef in order to have your questions answered.

The smoke point issue suddenly hit me when, after attending about 8 different community education cooking classes, I realized that the chefs very often quickly mentioned the smoke point as relevant to when they put the food in the pan, but they never explained the relevance.

In terms of the detail of my questions, I have always liked science stuff and I am intrigued by how much chemistry is involved with cooking. In fact, I've been reading a book called "The Science of Cooking" and it is not by a chef but by a scientist. I like a comment he made in the book, something to the effect that if you understand the chemistry of some of the cooking processes (rather than blindly following a set of directions), you will be able to make good decisions when you have to modify your recipies because you will understand the roles of different parts of the cooking process.
post #12 of 15
......are you supposed to match up the oil with the particular food you are cooking?
.......use an oil that has a smoke point of 1,000 degrees?
because there's no such (edible) oil

okay, in the veggie oil camp we got
olive oil
corn oil
canola oil
flaxseed oil
safflower oil
soy oil
coconut oil
sesame oil
peanut oil
......and , , , , whatever else I forgot . . .

they don't taste the same - some have a distinct taste of their own, some are more flavor neutral -
they have different smoke points ( x multiples as some can be had in various "refined" states) -
and last but not least,
they all don't cost the same.

if you like to deep fry and reuse the fry oil, you'll want to pick one with a higher temperature tolerance - those oils should last longer before 'degrading'

you don't need to "match" oils to foods - except possibly for taste reasons - and the there is no specific temperature the pan must reach +/- 0.00005F degrees before you dare put in a steak. the pan should be hot, the steak should immediately sizzle when put in the pan. excluding extreme temperatures and opinions, there's likely to be no noticeable difference in the results if the pan is 500' when you start or 400' when you start - when you put the steak in the pan, the pan will very rapidly come down the the same temperature anyway. you might get slightly more darker spots at the higher temp.

shimmer point: experiment - put fry pan on burner, put cold oil in fry pan about 1/4 inch deep, turn burner on, stand and observe appearance of oil as it heats up. looks just like it sounds <g>
post #13 of 15
Yes, there are a lot of places where adequate technique for one breaks down for the other.

Since you've talked to all of us, I think you might consider the different approaches Chef Ed and some of the more classically trained cooks like foodpump, oldpappy and I have. Chef Ed is frequently on a different page from the three of us, but he's never less right. He comes from a different perspective, used different tools, slightly different processes, and so on. But he speaks from a wide and deep knowledge base. I'm constantly impressed with how much he knows.

Don't sell the home kitchen short, or the work you can do out of it. It's a challenging environment. It's a lot harder for the same four cooks to feed four people each out of a well-equipped home, than to feed 16 covers as a kitchen brigade. But the home kitchen is so much more satisfying.

Dillbert covered this pretty well, I think. Generally, you match the smoke point to the type of cooking. For instance, you usually deep fry at slightly above 350F, so you want an oil that can withstand high temperature for a long period. Then you determine which oil that has a sufficiently high SP will best enhance the food to be cooked. Cooking is all about balancing complex dynamics. One thing effects another which changed a third, and all three need to harmonize with a fourth ... and so on.

There are some very high-heat, very neutral tasting oils -- but some people prefer other tastes. I think most home cooks keep a few cooking fats but not a wide range. I always have lard, butter, extra virgin olive oil, and corn oil on hand. Sometimes I'll buy something else for a special purpose.

Aha, steak specific! We want the pan hot enough to sear. We aren't using the oil for, pardon the expression, immersion contact conduction. We're using it to lubricate the steak and pan, and to help elminate hot spots.

"Shimmer point" is an expression I made up based on a phenomenon nearly all experienced cooks have observed. And, I'm by no means the first or even in the first 473,000 to use the word "shimmer," to describe it. That is, when a cooking fat gets hot enough to use for cooking -- no matter what it's smoke point -- the interface of the surface of the oil and the air right on top of it seems to "shimmer." I think this has something to do with small amounts of water evaporating out of the fat.

You da man!

post #14 of 15
Laughing thinking about this - for me it seems like it's about five seconds after adding the oil to the All-Clad sautoir sitting on a flame you could barely see. Dunno about ya'll but I can't keep these pans from running away from me.
post #15 of 15
I must add that when an oil reaches the smoke point, there is a risk that the oil might catch fire. One other thing, usually refined oils tend to have higher smoke points than unrefined or virgin oils

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