Thermometer Placement in Smoker - WOW, it makes a difference!

Discussion in 'General Discussion' started by pianov, Feb 28, 2016.

  1. I have a masonry wood-fired smoker (picture below). It has two shelves for meat - one just above where the hot smoke enters the cooking chamber and the other half way up. I almost always put my meat on the upper shelf. I have long had my temperature sensor about five or six inches above the upper shelf. And as I usually don't have the upper shelf full of meat, I think it has given me pretty good temperature readings for the cooking chamber. In the first picture below the lower section doors are open and the upper shelf is at the base of the half-cicle upper door.

    Today I started up the smoker at 9 AM and at noon put 30 lbs. of pork loin on the top shelf - that's three whole pork loins - and they just fit on the upper shelf - they occupy the entire shelf with only small openings for the smoke to migrate through. 

    I thought about how that might affect the temperature in the upper half of the cooking chamber. So I kept my temperature probe in its usual position above the upper shelf - but added a second probe - dangled it from the door lock to the lower section - so the second probe sits and inch off the inside of the door and about five inches below the upper shelf where all the meat is. The 207 degree reading is from the lower probe (between the firebox and the meat) and the 158 degree reading from the probe above the meat (between the meat and the chimney vent).

    WOW - a 50 degree difference between the lower part of the cooking chamber and the upper part. I expected some difference, but not that much! I suspect that as the meat heats up, the difference will be negligible. I also suspect that if I want to keep the smoker at 200 to 210 degrees, I need to be watching the second probe that is in the lower section of the cooking chamber.

    Just thought this might be of value to some.
    halfsmoked likes this.
  2. I always monitor box temp right at my meat. Generally 4 inches above the meat. May I say That IS ONE BEAUTIFUL SMOKER.
  3. Thanks for the compliment. I really like my smoker and it sure works well. I really wondered about making the top and doors out of wood - whether everything would warp and crack and fall apart. I originally built the smoker about 20 years ago, but about two years ago I rebuilt the smoking chamber (and firebox door) and added the upper half of the smoking chamber. But I've had seemingly real good luck with the wood - it provides lots of insulation and heat retention and only the inside lamination (five total) has cracked up quite a bit, but it is hanging on quite well. Below is a close-up of one of the edges of one of the lower doors. Pretty Douglas Fir on the outer lamination and box-store 2x4 spruce for the other four laminations.

  4. smokinal

    smokinal Smoking Guru Staff Member Moderator OTBS Member ★ Lifetime Premier ★

    That's not a smoker, that's a piece of art.


  5. halfsmoked

    halfsmoked Master of the Pit Group Lead SMF Premier Member

    [​IMG] a great looking smoker real art work. Looks like you get your temp problem worked out.  [​IMG] on smoker build.
  6. Thanks for the compliment, but I didn't have a problem with temperature. My point was to show that there can be a large temperature difference between below the food and above the food in a cooking chamber where the smoke travels up through the food.
  7. Thanks! A very kind thing to say.
  8. Thanks for the compliment. That is exactly where I have always placed my temp probe. But now I see that if I have a full rack of food and I keep the temp of the area above the food at 220 degrees, that means that the bottom of the food is going to get blasted my 270 degree heat!

    I was following Jeff's recipe for the pork loins - he says it usually takes about five hours. Every time I had smoked loins it took three hours or less. I think it was because the lower portion of my cooking chamber was 50 degrees hotter than my temperature probe (in the upper part of the cook chamber) was indicating. This time, keeping the lower part of the cooking chamber around 210, it took 4-1/2 hours to get the pork up to 240 degrees.

    I will be permanently mounting a temperature probe in the lower section of my cooking chamber. I think that will give me a more accurate "smoking" temperature.
  9. radioguy

    radioguy Smoking Fanatic

    You are right about temp variations. I bought a few oven thermometers so I could look at temps on different shelves. They are pretty accurate and in expensive.



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