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chocophile

Infrared/Laser Thermometers

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Ok Ok

but what does emissivity mean to me?

I want to point and shoot

I dont really want to get involved in ""emissivity"" unless you tell me why

:blink:

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Reflective surfaces can skew IR thermometer readings. Adjustable emissivity allows you to compensate for that.


This is my skillet. There are many like it, but this one is mine. My skillet is my best friend. It is my life. I must master it, as I must master my life. Without me my skillet is useless. Without my skillet, I am useless. I must season my skillet well. I will. Before God I swear this creed. My skillet and myself are the makers of my meal. We are the masters of our kitchen. So be it, until there are no ingredients, but dinner. Amen.

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I have a Raytech, but its not laser,,you just point it at what you want to measure and it does it ie pans grills etc, probably cheaper than laser and lasts longer?

Bud


Edited by qrn (log)

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I have the thermoworks one, it works great for me, and I thought it was the best value when I did my research.

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I've been using a ThermoTech TT1610, infared for 2+ years primarily for a wood fired oven. Accurate and reliable. High and low temp alarm set, laser indication, backlight, C or F, data store/recal function, low battery indicator, external K-type thermocouple measurement, lit LCD display. K-type range 58F-482, IR 76F-1652, adjustable emissivity setup. It maybe too much but I like having options available. Unfortunately it doesn't pour wine.


"I drink to make other people interesting".

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I have three thermometers that I use for everything but not the same things. One is a laser thermometer by Maverick, a thermapen from thermaworks and a cheap digital thermometer with a probe that goes in the meat or bread with a digital readout that sits outside the oven and sound an alarm when the target temperature is reached. The last one is not any special brand and need replacing every six months or so but I like all three and would not want to be without any of them.


Edited by Norm Matthews (log)

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The good about IR thermometers:

-You never have to clean them, or sanitize them.

-You never have to get too close to what you want to measure

The bad about IR thermometers

-Many don't give accuate readings with reflective surfaces

-Many don't give accurate readings with black or dark surfaces

-Only gives the surface temperature, not the core temp.

-You get what you pay for, the cheaper ones can fluctuate by as much as 3 degrees +or-

-They do tend to eat up batteries

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Ok Ok

but what does emissivity mean to me?

I want to point and shoot

I dont really want to get involved in ""emissivity"" unless you tell me why

:blink:

Different materials/surfaces emit IR differently even when they are at exactly the same temperature. (They have different "emissivities".)

Which means that an IR thermometer will give different readings depending on what you are pointing it at.

And that means that as a general "point and shoot" NONE of these things is very accurate.

Emissivity adjustment allows you to 'calibrate' the instrument so that its reading (for a particular surface) is more accurate.

Or alternatively, you can calibrate the thing at the user end, applying an offset as you work based on experience or previous calibration. "When the oil is at 175C, I know it shows as 160" - or 180 or whatever.

My (far from extensive) experience is that (variably shiny surfaces apart) they are quite consistent (giving consistently the same reading - whatever that might be - from the same surface at the same temperature).

One additional point - the distance ratio. With a 4:1 you do need to get quite close to what you are measuring (or looked at differently, it averages over a large area) whereas a 12:1 allows you to be 3x further away when measuring the same area (otherwise you measure a smaller spot from the same distance).

Wide angle or telephoto - there is a choice!

Any laser fitted is simply to indicate the approximate centre of the measurement area. A laser takes no part in the measurement and does not indicate a 'point' being measured - the thermometer is always measuring from an area (whose size varies depending on how far away from the surface the instrument currently might be).

It doesn't even need to have a laser. But people like them ...

I suggest you get a chinese cheapie from eBay and play with that until you know that you need something better (or perhaps a specific job to do with it, like chocolate).


Edited by dougal (log)

"If you wish to make an apple pie from scratch ... you must first invent the universe." - Carl Sagan

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I would like to get an infrared thermometer and would like to know what one to purchase. In particular, I would like one that would give me accurate readings on the temperature of oil when deep frying. Thank you.

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Elsie,

I use one for deep frying but I doubt it is very accurate. It gets me in the ball park and that works for anything I am likely to attempt. They are simply not designed for accuracy when measuring liquids. I am more than happy to sacrifice scientific accuracy for the convenience.


Anna Nielsen aka "Anna N"

...I just let people know about something I made for supper that they might enjoy, too. That's all it is. (Nigel Slater)

"Cooking is about doing the best with what you have . . . and succeeding." John Thorne

Our 2012 (Kerry Beal and me) Blog

My 2004 eG Blog

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Infrared thermometer's accuracy varies depending on the surface you're measuring, since every surface has a different emissivity.  Most IR thermometers can adjust the emissivity setting so you can get an accurate and consistent reading on any surface, so long as you're always measuring the same surface. I have a thermoworks IR thermometer (got it during one of their open box sales) which also has a type K thermocouple input.  I can use that thermocouple input to directly measure the surface, then adjust the emissivity setting so that the IR temp. matches the thermocouple temp.  Thermoworks also has a list of quite a few different surfaces and their typical respective emissivities on their website.

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What others have said....

 

Please bear in mind that an IR thermomter will only measure surface temperature, not what's under the surface.  Also, cheaper units are affected by reflections from S/S cookware

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I would like to get an infrared thermometer and would like to know what one to purchase. In particular, I would like one that would give me accurate readings on the temperature of oil when deep frying. Thank you.

 

In addition to what KennethT said, also you need to understand D:S ratio when selecting one. The distance-to-spot ratio (D:S) is the ratio of the distance to the object and the diameter of the temperature measurement area. For instance if the D:S ratio is 12:1, measurement of an object 12 inches (30 cm) away will average the temperature over a 1-inch-diameter (25 mm) area. 

 

Also, reflectivity effects all thermometers measuring by IR radiation, does not matter cheap or expensive. The ones with adjustable emissivity control allow you to compensate the effect.

 

dcarch

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This morning I received notice of an open box sale for Thermoworks.  Two or three different infrared thermometers are on sale, and the prices seem reasonable. 

 

I was wondering if by using an infrared thermometer, cooking results can be improved.  I've always been curious about what is going on while cooking, and I know that temperature control can be an important factor, but never having used (or seriously considered) an infrared thermometer, I don't know how worthwhile they are.

 

For those who have used them, have you noticed better results?  In what ways, and for what foods or cooking techniques, have you used these thermometers?  Are they better for certain cooking tasks?


 ... Shel


 

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I think IR thermometers are great if you're constantly measuring the temperature of a single item. For instance, member Kerry Beal uses her IR thermometer to check chocolate temps (while stirring to even out temps throughout the bowl).

The problem is that different surfaces emit infrared differently, so the temperature you read is not necessarily accurate. You can't use the same setting to check the temp of the oven wall, versus the surface of a chicken.

Plus, the IR thermometer only gives you surface temperature - so, back to the chicken example, checking the surface temp tells you nothing about how well the chicken is actually cooked internally.

One advantage may be to use it to check the temperature of a skillet prior to use - but I think a moderately experienced cook can do this just as well by judging the appearance of a little oil and how it shimmers, or how a drop of water dances....

ETA: I'd be curious to hear other's experiences for people who use them all the time for cooking.


Edited by KennethT (log)
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Tools cannot in themselves improve anyone's cooking. How they are used may.

As has been pointed out, IR thermometers have their uses, but they aren't the be all and end all. They only measure surface temperature. 

 

Take a hamburger patty and grill or fry it. Measure with your IR thermometer then flip. The side just facing the fire will be much hotter than the other. Then watch that side cool rapidly. Then flip again. And measure again. 

 

But the problem is you still have no idea what the internal temperature is, which is what matters most.

 

I use my IR a lot, but only in situations where it is appropriate. Four bottles of beer in the fridge. Which is coolest?


Edited by liuzhou (log)
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one other thing :  make sure you understand emissivity if you want an 'accurate' temp

 

http://www.thermoworks.com/emissivity_table.html

 

cheaper models are 'fixed'

 

that shinny pan will give you a much different reading than that black cast iron pan, if that makes any difference to you.

 

as far as I can tell the fixed emissivity ones are set for darker material

 

so that shinny pan will be off, by who knows how much.

 

harbor freight has a fixed inexpensive one :

 

http://www.harborfreight.com/infrared-thermometer-93984.html

 

there is a store near me so its easy to get to for me.. probably not for many of you

 

and like BB&B, they always have a 20 % discount coupon.


Edited by rotuts (log)

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I bought a very inexpensive one quite some years ago and have found it useful for a couple things:

 

- checking the temp of liquids (while or immediately after stirring); useful for knowing if it's safe to add yeast to the milk I scalded

- checking the surface temp of my pre-heating non-stick skillet after posts here freaked me out; don't remember the number but was surprised at how low it was

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I mostly use it to check the temperature of a cooking surface (pan/grill) before adding food. I could see how it would be useful for working with liquids (that one is constantly agitating). In either event, a probe or Thermapen is a much more useful tool all around -- but for much different purposes.

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as far as I can tell the fixed emissivity ones are set for darker material

 

so that shinny pan will be off, by who knows how much.

 

This fits my experience. I sometimes use one to check the pan temperature before making things like crepes. It doesn't make me a better cook, but it's nice to know the pan is ready without having to make a couple of lousy crepes first. For this it only works on cast iron or teflon; on stainless surfaces the readings are so far off, it's almost as if I'm getting the temperature of whatever's reflected in the pan's surface.

 

It would theoretically be helpful to check baking stone temps for pizza making, but mine doesn't go high enough. I haven't found it useful for measuring the surface temp of food.

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Notes from the underbelly

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I got one "free" with the purchase of other stuff from Thermoworks.

 

as pointed out, the emissivity factor of various surfaces requires any IR device be properly calibrated if you need an accurate temperature number.  for "it's hotter / it's cooler" they're fine.  do not believe the "it auto calibrates" nonsense.

 

I have yet to find a real-cooking-life use for the thing.

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I want to thank Shel B for starting this. I don't have anything to add. I do have a UV thermometer but have not used it much lately. I used to use it when I did more deep frying. But I went to the Thermoworks site because of this and noticed a new product called Dot. It's an oven alarm thermometer. I just ordered one with a probe designed for measuring the air in my smoker. Unlike other such alarms, the probe wire is suppose to stand up 700º. I hope it works out. 

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