# Surface temperatures



## von milash (Jul 1, 2009)

does anyone know of a way of measuring the surface temperature of a pan? Obviously, if your oil reaches its smoke point, you're at least that hot. But that's not exact... your pan will surely be hotter. Also, does anyone know the hottest a pan will get (roughly) on high heat on a home oven? Commercial? We always talk about XdegF inside an oven, but we NEVER talk about the actual temperature of a pan on the stove top. Doesn't make sense... one so precise, the other so crude and subjective. 

Again... the scientist in me...always looking for absolutes and structure and exact numbers for repeatability..... but in all my years in lab I never saw anything to measure the temperature of a flat surface. surely it can be done though.

Thoughts? Ideas?


----------



## von milash (Jul 1, 2009)

for example.. if i was to say in a scientific journal, "mix chemicals A and B, dissolve in sovent C and heat," but fail to give a temperature for the reaction, other chemists would think I'm a joke. Heat at what temperature??? On the other hand, we routinely say, "in a hot pan..." 

again... no true science behind that, and an insult to the study of molecular gastronomy...


----------



## french fries (Sep 5, 2008)

On one hand I love understanding all the science behind cooking, on the other hand I can't picture myself cooking with a thermometer and and ultra-precise scale in a pressure controlled room and wearing a hygienic mask. :lol:

Having said that, Maillard reaction happens at 310 degrees Farenheit, so I suppose that's the heat you want from your pan if you want to brown something.

If you'd like to experiment you can try this:

YouTube - HD Pan Frying: Testing for Proper Pan Heat

Personally I kinda get a feel for the temperature of my pan by placing my hand about 2 inches above its bottom for a couple of seconds. When I sense it's hot enough I put in the oil, and make sure I can see "legs" forming (the surface of the oil is no longer smooth). At that point I know the pan is ready to brown my food.

Obviously, if you want to sweat something you'll want a bit less heat...

But let me ask you this: do you feel the need to weigh the exact amount of oil you're pouring in your pan, down to the 1/10th of a gram? Or when the recipe says "2 Tbspn", do you grab a Tbspn measure and carefully measure two tablespoons? Or do you just kinda pour a bit of oil, just enough to coat the bottom or so?


----------



## demolitron (Sep 3, 2009)

There are a few ways to measure the surface temperature of a pan but the best is probably an infrared thermometer. However, these are not always 100% accurate. They measure the black-body radiation and that varies depending upon the temperature and the emissivity of the material being measured. 

Most IR thermo's are calibrated to accurately measure the temperature of flat black and organic objects. These tend to have an emissivity of ~0.95. A shiny stainless steel pan has an emissivity of ~0.75. This can make a big difference.

A black teflon coated pan would read just fine with a standard IR thermo. But a shiny pan would require you to compensate the IR measurement. I would use a thermocouple attached to the pan and turn the heat to low. Then wait for the temperature to reach equilibrium and measure the temperature of the pan with the IR thermo and record it along with the thermocouple temperature. Then raise the heat a little bit and measure again. Using a few data points you would then be able to calculate a compensation factor you could apply to the IR thermo's measurements and get an accurate reading.

Some IR thermometers have an adjustment to change the assumed emissivity of the material and then provide accurate results.

As far as the maximum temperature you can achieve on a home range is highly variable. It depends on how much heat energy can be produced by the burners. Even if we pick a "standard" burner output say 30,000 BTU that won't help much. The size of the pan, the material the pan is made of, what coatings it has, the density of the air, humidity, air velocity, and room temperature determine, along with the total heat input, what the temperature will be when the pan reaches thermal equilibrium.

But in general a typical home range will be able to heat a variety of pans to over 660F as many people who have poisoned themselves with burning Teflon can attest. And some home ranges can, with the right pan and conditions, melt some aluminum alloys at a temperature in excess of 1000F. 

Cooking and science are made for each other! Have you ever looked deeper into the maillard reaction? I thought it was interesting that at different peak temperatures different aromas and flavors would be produced. So if you sear your meat at say 500F till GB&D and then another piece at 400F till its the same level of GB&D they will taste and smell slightly different. So when a recipe says sear the meat, the exact temperature of the pan would be required to achieve the right taste...

I guess that's why a super hot wok is required to give the food that "breath of the dragon" flavor. Just cooking it at lower temps till very slightly blackened just doesn't do it right.


----------



## demolitron (Sep 3, 2009)

This is a cool video. I never knew about that water trick myself. Thanks.

As for me... yes I will admit that I do use a kitchen scale in grams to measure what I deem to be critical ingredients. But 2 Tbs of Oil isn't going to matter all that much. I use the scale all the time when Baking.


----------



## andydude (Dec 30, 2008)

Hi Von Milash,

Something like an infrared thermometer might fit the bill for reading surface temperature, although I'm not sure how a coating of oil would affect the reading.

Edit: I see Demolitron posted useful info re IR Thermometers while I was typing this, I'll leave the link available just to give easy access to one example of it's kind.

Amazon.com: KINTREX IRT0421 Non-Contact Infrared Thermometer with Laser Targeting: Home Improvement

I started off very recently with the same sort of questions - what the heck is a hot pan and how do I know what temperature it is? I think now it was not the most profitable way of looking at it - I don't worry about exactly how hot the pan is - so much as is the pan letting me know I'm at the right point, and am I heating the pan in such a way as to maintain control over the heat at that point?

I think learning to recognise key events and what they facilitate are more useful than always knowing exactly how hot the pan is at any given time. Most, if not all events will have some visual indicator that will assist in knowing when to add oil, when to add product, what's happening to that product. If it's something like a poaching liquid with very little visual indication, then a normal instant read thermometer would let you know if you're within that range.

The good news is, these things are based on scientific events, desirable changes that occur at given points that will satisfy your scientific background. Wonderful stuff like the Maillard Reaction, coagulation of proteins, and a whole lot of stuff that other folks can express more usefully than I can.


----------



## ed buchanan (May 29, 2006)

In cooking what difference will it make ? If you are supposed to fry at 360 ,which has already been figured out and tried by the poster of the recipe or formula. The oil temp of 360 is what matters not the temp of pan. Seems like making a suggested factor more complicated. Most people on this site I believe are interested in cooking, and the outcome of the final product.:chef:


----------



## von milash (Jul 1, 2009)

Ed I believe you're underestimating the potential of knowing the exact temp of your pan. If there's any science in cooking, and I think you'd agree with me that there is, than this would SURELY qualify. If you want to go on as you are, fair enough. you have a lot of experience. I however, believe that for every cut of meat, at any thickness, there is an optimum temperature at which the meat with brown, in combination with allowing the internal temperature to come that desired. Being off by a hundred degrees, which is not determinable by eye or the palm of your hand, will surely yield different results. 

So if there's an easy way to measure the surface temperature of your pan in the event that you are not using an oil, how would that be making things more difficult? Would you guess at the temperature of your oven or deep fryer? IMO, NOT knowing makes things more difficult. :chef:

I also believe this would be great for knowing the temperature of your grill AT the surface of your grates. The steamboat technique, although a decent ballpark, can surely be improved upon. A regular old high temp thermometer can do that though. And a damned safe oven mitt.


----------



## ed buchanan (May 29, 2006)

Almost all meat de-natures at 140.f. And why do I want to know the temp of the pan when my oven temp checks out at 325 or 350? And if something is off 100 degrees, like in oven, or fryer, or grill, then there is something wrong like a thermostat. If a saute pan, then true there is no thermostat, but then you have option of regulating bottom heat, and some metals will conduct and hold heat different then others. I am not argueing but I see no use for why I should worry about other temps.


----------



## willie24 (Aug 13, 2008)

Von - Yes, there is no doubt science in cooking as witnessed by proportions in recipes, cooking times, humidity concerns, proper temperatures of what you're cooking, etc. With all due respect, I'm not sure that knowing the exact surface temperature of my pan or grill is going to improve anything.

I put a lot of faith in holding my hand over a pan to tell me when I'm ready to cook and I can eyeball the fire in my grill well enough to know when to throw on a steak. That comes from doing it for many years and learning from your mistakes.

I'm with Ed on this one - cooking is not an exact science. There's an art and a passion to it that requires more than a pure scientific approach. I like all the variables that make cooking not so exact.


Willie


----------



## demolitron (Sep 3, 2009)

Ovens are horrible at maintaining temperature! The last three oven's I've had would swing about +/30F. That's a 60F peak to peak difference. Even then the average temperatures were off by around 5%.

I usually put a layer of fire bricks in the bottom of the oven to provide a large thermal mass. It slows down the pre-heat but in exchange is keeps the thermal swing down to around 20F peak to peak. 

A normal oven thermometer is not fast enough to see these large swings usually. A high speed K-Type thermocouple can react fast enough to see the swing.

Convection ovens are usually much more accurate because the high airflow reduces the thermal lag of the thermostat. Ideally oven makers would change from a simple trip-point hysteresis thermostat to a binary state PID (Proportional Integral Derivative) that could learn the thermal cycle of the oven with its food and keep a nice even temperature. But that would get expensive...


----------



## dc sunshine (Feb 26, 2007)

I concur. What I find if you're using a saute pan, not matter whatmaterial it is, if you add oil, watch it till it moves on its own, add a little pat of butter, once it stops foaming - you're ready to sear your meat. Its hot.

Using a dry pan for pre-oiled meat - the hand over the pan is the go. If you can hold it there only long enough to say "one Woolamaloo, two Woolamaloo" - you have high heat for searing. (Woolamaloo is a small town in the outback, but the method works).

Add 2 more Woolamaloos for medium heat, 2 more for low heat 

Or, put the edge of a piece of meat on the pan. You get a sizzle straight away - it's ready.


----------



## petemccracken (Sep 18, 2008)

Remember, cooking is an ART, not a SCIENCE!

We deal with biological entities, be they starch, vegetable, or protein, though the characteristics fall within a fairly narrow range, there is still a RANGE to contend with and a good cook adapts to the variables at the time.

Yes, it is good to understand temperatures AS LONG AS ONE UNDERSTANDS THE ADJUSTMENTS NECESSARY TO ADAPT TO THE VARIABILITY OF FOOD PRODUCTS.

That is why cooking is an "art".

(well, then there is sous-vide  )


----------



## pete (Oct 7, 2001)

Of course you'd want to know at what temp. the reaction takes place, but when conducting experiements are you recording the temperature of the solution or are you recording the surface temperature of the vessel holding the liquid? Do you know the exact temperature of the flame you are using to heat that said mixture? Sure you may know the theortical temperature of the gas you are burning to heat the vessel to heat the mixture, but do you take into account the gas to oxygen ratio, do you consider the air currents in the lab that might be affecting the flame. Do you know the exact properties of the vessel that is holding the mixture so that you can determine exactly its rate of heat distribution? That is an awful lot of variables to take into account when ultimately on the only thing that truly matters the the temperature of mixture itself. The same is true of cooking. What matters is the temperature of the food itself and then the only times cooks and chefs are really concerned about ballpark temperatures is when cooking meat to doneness and even then those temperatures are usually given with a range. I see where you are trying to go with this, but really, you are overthinking it, and making it more difficult than it needs to be.

On top of all that, when cooking most meats, cooking is only part of the equation. After cooking, then there is the resting period which most meats need to be properly prepared. So even if you got the heat of the pan down exactly to the "optimum" temperature, you then have a whole new set of variables to deal with during the resting period (ambient room temperature, air currents, thickness of the meat, type of cut, tenting vs. not tenting the meat, material used to tent,etc.).

Finally, one more word about doneness temperatures. Unlike many chemical reactions that are done in a lab, missing a temp. by a few degrees is not catastrophic. As I stated above, doneness temperatures are usually given in a range of 5 degrees or so, and even then you get conflicting answers as to what connotates a certain doneness. Even for items that require more exacting measurements such as candy making, cheese making, beer brewing, etc., it is the liquid that is measured and the fact that the liquid in contact with the surface of the pot might be at a slightly higher temp. makes no difference.


----------



## blueicus (Mar 16, 2005)

And one tool already exists for that, the immersion circulator. Of course, immersion circulators can't heat things to maillard temperature so we have to look elsewhere. Induction cooktops allow the user to control the temperature of the pan relatively precisely (presumably a more expensive unit can more precisely control the temperature of your pan), which I can really only see it being useful if you're going to make fried chicken on the stove top or shallow fry a schnitzel. Of course, I've also used induction burners to melt butter without burning it and to keep things warm without boiling it.


----------

