Why deos a hot grate damage a thermometer probe?

Discussion in 'Meat Thermometers' started by josh, Aug 3, 2007.

  1. I have been laying the shaft of my thermometer probe directly on the grate with the point between the bars on the grate to check the temp. in my smoker. On my thermoreter probe you can see on the tip where it measures heat. I have read many times that you should not put the probe on the grate because the hot metal will damage the probe. Is this because the grate is metal, or because it is hot? Why would the grate be any hotter than the temp. inside the smoker? I guess I need to test my thermometer again to see if it is still accurate and that I haven't damaged it. [​IMG]
     
  2. peculiarmike

    peculiarmike Master of the Pit OTBS Member

    Can't say the probe contacting a hot grate or rack would damage it. It's made to take heat. Only thing would be contacting hard enough to cause physical damage. You are correct, the grate or rack is only as hot as the interior temperature of the smoker.
    The big issue would be to not push it through what you are smoking. And you do not want the probe to touch bone if what you are smoking has bones in it, gives incorrect reading.
     
  3. pigcicles

    pigcicles Master of the Pit OTBS Member SMF Premier Member

    I guess there are a few issues with this Josh. One being that some have said that their probes have shorted out when touching the metal grates.

    Another being that if you leave the probe on the grate and it doesn't short out, the metal grate will not allow the probe to pick up the temperature spikes as easily as purely reading air temp.

    It is advised that we use a sacrificial potatoe (potatoe chunk), or some other item, to hold the probe off the grate and read only the air temp. I don't know if the probes short or not, but why take an increased chance to prematurely kill your probe?
     
  4. doc

    doc Meat Mopper

    Josh,
    It probably has something to do with the conductivity of the metal in the grates. The metal is going to hold more heat than the air. It's how you get grill marks.

    You cant get an accurate reading when the therm is on the grate, look for some probe clips or do what I do and sacrifice a small potato by using it as support for the probe. Just leave about an inch of it stuck in the potato by the bend. That'll do it for you.
     
  5. gypsyseagod

    gypsyseagod Master of the Pit OTBS Member

    so what about the enamel ceramic covered grates ???
     
  6. hawgheaven

    hawgheaven Master of the Pit OTBS Member

    If the probe being in contact with the grates is bad, what about being in contact with the metal clip that holds the probe (that comes with the ET-73)...? It clips directly to the grates and is constructed of metal... it is gonna be the same temp as the grates...

    Just curious...
     
  7. Thanks for the information. I did not think about the grate maintaining temp. for a while after the ait temp. changes. But wouldn't the potato also do the same? I guess the best thing to do would be to haing the probe so it doesn't touch anything but air.
     
  8. squeezy

    squeezy Master of the Pit OTBS Member

    You know, smoked potatos are rather good, so instead of sacrificing a potato, use one and put a few more around it for dinner ... eh? [​IMG]
     
  9. doc

    doc Meat Mopper

    Good point...Maybe its a mass/surface area thing? Or perhaps the clips are made of a less conductive metal,like aluminum?
     
  10. pigcicles

    pigcicles Master of the Pit OTBS Member SMF Premier Member

    IMHO I don't think that the probes "short" out. I've never had one do that when touching metal surfaces. My opinion of it is that the point of contact creates a hot spot that my burn out the probe enough to cancel any signal sent back to the unit. As Doc stated I think that the surface area of the probe can take the internal ambient air temp, but the point of contact may be too much - in some cases.

    Your skin can take a lot more ambient air temp than it can a point of contact at the same temperatures due to the surface area. Maybe I'm wrong - But that's how I'm seeing it.

    Keep Smokin
     
  11. kueh

    kueh Meat Mopper

    You're not going to damage your probes by allowing them to touch the metal grate (shelf) of a smoker. The issue is accuracy. While the air temperature inside a smoker will fluctuate quickly, the metal grate will fluctuate very slowly. The only time you might damage a probe would be if you tried using it on a grill where temperatures can exceed 500°. And that's with prolonged exposure. Just touching the grill for a second will not make the probe explode or anything like that.
     
  12. moltenone

    moltenone Smoking Fanatic

    the wires in the tip of the probe are connected together by a heat sensitive
    epoxy,if the temp exceeds the units range damage can occure.


    mark
     
  13. catfish

    catfish Meat Mopper OTBS Member

    Well I just took a probe with some broken wires apart lastnight. I was able to check out the inside there is no electrical connections to the metal outside of the probe. Mine was wired with 2 small gauge stainless steel wires. The end was a sensor tiny tiny sensor in some glass. The whole thing was insulated from the metal probe. Letting the probe hit the grate might break the glass? Or could cause a heat spike if you had the tip on the grate which could damage the small sensor by a drastic temp change from the hot metal mabey? well that said i was able to fix the probe and it reads fine again. And hopefully gave some insight on the inside of a probe. Looks a little trashy but it works now.

    Some said the metal cover of the wire was part of the connecton I did some continuity checks it is just there for proection of the tiny wires. It had no connection to the probe plug but was crimped into the pobe.
     
  14. squeezy

    squeezy Master of the Pit OTBS Member

    1. The air temp. is what we are trying to read
    2. I believe, only the 1/4 inch tip is reading the temp.
    3. So, it needs to be free of metal contact, however that is accomplished.
     
  15. ajthepoolman

    ajthepoolman Smoking Fanatic OTBS Member

    Where is Alton Brown when you need him? He could probably explain this in his show with way too much detail.
     

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