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Laser/infrared thermometer - please help

m
ManhattanLawyer Nov 12, 2008 05:25 PM

I was at the Chocolate Show in NYC this past weekend, and Jacques Torres had a laser thermometer to test the temperature of his chocolate. This seems like an excellent idea, because I hate having to stick a digital temperature into meats like turkeys to test for doneness. So, does anyone know how accurate these are for cooking? Does anyone have one? Where did you buy it, and what brands do you recommend? Thanks!

  1. Romanmk Nov 20, 2008 10:34 AM

    Just to clarify, what about checking the temperature of a 1/4" to 1/2" of oil for pan-frying? How about 1 cup of oil in a wok? What about deep frying oil?

    1 Reply
    1. re: Romanmk
      HaagenDazs Nov 20, 2008 10:42 AM

      It's not best suited to check things like that with an infrared thermometer. Remember you are measuring the surface temperature of these items. There are also problems with trying to read a reflective surface. The IR thermo won't read the reflective surface very accurately. If you're measuring oil for deep frying you should have a thermometer in the oil itself. The minute you drop something in the oil, you're going to get some steam and if the steam is dense enough, you're going to get temp readings of the steam not the oil. You might have some luck measuring temps in a shallow pan if the background surface is black, but I wouldn't bet on it.

    2. g
      grant.cook Nov 17, 2008 07:01 PM

      Chocolate relies upon even, slow heating of the melting solids - you don't want much of a gradient when melting, so you stir a lot to keep any one spot from overheating. Surface temp might be a close approximation there. The gradient from the outside surface to the inside core of a standing rib roast is huge - don't use a surface temp thermometer.. you still have to stick something into it..

      If you want the thinnest probe possible, get a thermocouple thermometer. Not cheap, but thinner than the basic ones you are going to get at your run-of-the-mill kitchen store.

      1 Reply
      1. re: grant.cook
        Monch Nov 20, 2008 05:24 AM

        Howdy,

        Part-time Hound and full-time Industrial Purchasing Manager.

        Thought that this unit might interest the folks on the thread: http://www.maxtool.com/index/Digital_...

        I ordered one (am a bit of a gadget hound) and really like it for testing pan temps prior to cooking. Of course, it ONLY reads the solid-surface temp, as noted above.

        But for $60, it's a nice little item to have in the kitchen arsenal.

      2. t
        ThreeGigs Nov 13, 2008 05:37 AM

        For testing a turkey for doneness they are useless. Surface temps only
        I have a Cooper laser infrared "Food Safety" thermometer, like what's used commercially for foodservice. I gave my ThermoPen away after I got it.

        If you want to get an infrared thermometer, compare the test size/distance ratio. On my thermopen, it was 1:1, meaning if I was 6 inches away, it gave the average temp of a 6 inch circle. My Cooper is 4:1, so 6 inches away yields a 1.5 inch circle, much better for checking out hotspots. Plus it's a 9 volt battery, cheaper and longer lasting than the button batteries in the ThermoPen.

        3 Replies
        1. re: ThreeGigs
          UnConundrum Nov 13, 2008 05:10 PM

          If you check the link, there are several models that are combinations. They read IR AND they have a probe for meats, etc.

          1. re: UnConundrum
            t
            ThreeGigs Nov 15, 2008 04:45 AM

            Bonjour, if I remember correctly, seemed to be the 'standard' IR/probe combo thermometer.

            1. re: ThreeGigs
              h
              hobbess Mar 4, 2011 11:24 PM

              Anybody own the Bonjour?

              I've been seeing it on clearance, but I'd want some feedback from chowhounds before I buy it.

              On Amazon, some people claim that the Bonjour measured temperature is perfect and others claim its off. How would you know if its measuring surface temperature correctly?

        2. j
          jerry i h Nov 12, 2008 08:30 PM

          Well, I have gotten into more than one knock-down-drag-out-fight with my fellow foodservice pros over this one, but here goes anyway:
          1) They are super accurate, but only for solid surfaces (think the surface of the engine block in a car). They can be re-calibrated to be accurate for liquid, but this requires an adjustable reflectivity coefficient, usuable by someone who knows what this means.
          2) They only measure the surface. So, it will not work for a roast beef where the center is totally different from the surface. But, in a bowl of chocolate, it is accurate if the chef has just mixed the bowl.
          3) You can roughly re-calibrate the IR, by taking a super accurate digital probe thing (like the Thermapen), and creating a chart of different chocolate temps as measured by the digital thingie, and recording what the IR says for the same temp. Then, once you have a complete chart, you shoot the IR at the thoroughly stirred chocolate, and look up what the real temp is.
          4) IIRC, my cheap whethear station IR thing reads exactly 3 degrees high in the range of 85-95 for tempering semi-sweet chocolate. So, if it says 90 degrees, the actual temp is 87. Course, this would be a different temp if it were milk or white or fake chocolate.

          1. Joe Blowe Nov 12, 2008 06:28 PM

            "This seems like an excellent idea, because I hate having to stick a digital temperature into meats like turkeys to test for doneness."

            You CANNOT take the *internal* temperature of roasted meats by measuring the *exterior* temp with a laser thermometer. Continue sticking your meats ;-)

            P.S. I have a Thermapen Original (http://www.thermoworks.com/products/t... ) and I wouldn't give it up for anything...

            1 Reply
            1. re: Joe Blowe
              k
              Kelli2006 Nov 12, 2008 06:43 PM

              I agree completely that I-R temp guns have limited uses, but they are very useful for testing brick oven temps, BBQs and occasionally candy or chocolate.

              The Thermapan is a excellent digital probe, if a bit pricey.

            2. UnConundrum Nov 12, 2008 05:42 PM

              Check out ThermoWorks... they make the Thermapen :)

              http://www.thermoworks.com/products/i...

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