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DizzyPC

Dome Temperature confusion on slow and low

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Have had a the Kamado Joe Classic 3 now for a few months and absolutely love it. 

 

This weekend did my first weekend pork shoulder (9.5 lbs) and am very confused my temperature readings. 

 

This was meant to be a trial run for fun and a few other things came up so started later then I planned.  

 

1. Started it up at around midnight at night and got it going and stable at around 230F.  Placed on a FlameBoss 400 (just out of box) and set to 230F and went to sleep.  I placed the alligator clips closer to the meet than to the centre.    

2. At 8 AM checked the FlameBoss app and the grate temperature was 230F, but after 8 hours the meet was stuck at about 145-148F.   Went downstairs and the dome temperature read ~180F.  So readjusted and no change and then checked with a different electric meet thermometer (which I lay across the grate) and that read 250F.  

3. Over day opened up the vents more and increased the dome temp to 240 and the grate temperature continued to read about 40-50 degrees more throughout the cook.   Eventually after about 15 hours finished the meat.  (I had to leave again for a few hours during this part)

4. Just for testing I attached the the aligator clips to the Dome temperature probe and was hitting >50F higher on the FlameBoss app.   I then checked in boiling water with 4 different thermometers and the Flameboss grate and meat probe and my other meat thermometers were all within a few degrees.  

 

My questions:

1. Why is there a 50F degree difference between the grate and dome reading. I've read some difference is normal - but this seems more?

2. In boiling water the flameboss seems to be accurate which makes me suspect the dome temperature is off.  But after 8+ hours of cooking my shoulder was stuck at 147F - which suggests I probably was cooking at about 185F?  

 

Thanks

       

   

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You just need to adjust the dome thermo. The longer a cook goes on the dome and grate temps become closer. If you were measuring the dome temp with the Flame Boss at the dome then the dome thermo is off. They should’ve been equal or just slightly off. The meat is a different story and seems on par with the temps you were cooking at

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1) Location, location and location... the three most important aspect of temperature readings. 

 

We all tend to use a (presumably accurate) dome thermometer because it's in a good spot and it doesn't move, so its readings are more consistent. It's only shortcomings are response speed (slow) and the fact that I sit too far away to see it. That's where remote thermometers come in, and so location matters...

 

My preference is in the exit vent, which is generally close to or higher than the dome reading. 250F exit gives me 225F grate at the end of the cook, when things are stable, but not the beginning. Food temperature matters, too. 

 

2) Welcome to BBQ! Is this your first stall?

 

Low and slow cooks, at ~225F as you did, have four phases

- cook fast (~+50F/hr.)

- stall (no change for hours once you hit ~160F)

- cook slow (~+10F/hr.)

- rest (slow cooling once it's cooked)

 

Time varies a bit based on the size and shape of the meat, but it's 1.5-2 hrs./lb. so yours was done right on time!

 

How was it? Do you have pictures? What's next?

 

HAve fun,

Frank

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Your dome thermometer could be off  I take it that the dome thermometer didn't read 185 when you went to bed so i'm assuming that perhaps the fire died down and the ceramics cooled off and when the flame boss  finally got it going again the grill temp showed the heat from deflector plates but the ceramics were still cool  affecting the dome thermometer Does the flame boss app show a temp graph? I had something like this with my heater meter. I quit using the blower till i learned how to control the fire with just the vents . JUst like learning how to control the vents you also have to learn the flame boss. 

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Just another thought. Not familiar with classic III does it use ceramic deflector plates? If it did were they close together with no gap between them?  If there is a gap and the probe is above this  you could be getting a high reading . I agree with John pay more attention to the dome temp.

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Thanks everyone for the feedback!

The pulled pork did turn out great!  Clearly though on the next one I need to be a little more hands on at the beginning until I get a better sense of control of the heat!

Dave

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Trust your Flame Boss 400 on the overnight cooks and disregard the dome thermo. However, you’ll definitely want to calibrate the dome thermo for the times when you’re not using the Flame Boss. Digging out your electronics for cooks less  than 3 hours is a pain. Below is a screenshot from my Flame Boss 

DA0550EA-78D6-4911-BCA7-DC1AA762AE72.png

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Running off of dome temp. is fine once you know your grill and understand the temp. deltas between the grate and dome for the type of setup you are using. I almost miss-timed a pulled pork cook for a party because I didn't know that that same setup on my KJ Classic resulted in a 25 degree delta between dome and grate temp. inside the area of the drip pan where the food was cooking and 50 degrees on my BGE XL. For a beginner IMO dome temp. is much easier to go by because they have yet to learn that where you place the grate probe matters and can give misleading readings.

 

Another thing I hear a lot is how someones dome thermometer is way off, I've yet to check one of mine and have it actually be off. The thermometer is usually accurately reading the temp. of where in the grill it sits.

 

 

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1 hour ago, Kamado Tom said:

 

Another thing I hear a lot is how someones dome thermometer is way off, I've yet to check one of mine and have it actually be off. The thermometer is usually accurately reading the temp. of where in the grill it sits.

 

 

 

Manufactured parts are sometimes faulty. The original poster said he tested  4 thermos in boiling water. If all four were close/verified, then the dome temp should of been the same as the Flame Boss if it was clipped to the dome thermo. He just needs to the remove the dome thermo and calibrate it and verify it in boiling water like he did the others. I think his Flame Boss did what it was supposed to do and the meat cook time doesn’t seem unreasonable. Many things can be done such as wrapping or bumping up the temp from 230° to speed things along. 

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17 hours ago, Drusen said:

 

Manufactured parts are sometimes faulty. The original poster said he tested  4 thermos in boiling water. If all four were close/verified, then the dome temp should of been the same as the Flame Boss if it was clipped to the dome thermo. He just needs to the remove the dome thermo and calibrate it and verify it in boiling water like he did the others. I think his Flame Boss did what it was supposed to do and the meat cook time doesn’t seem unreasonable. Many things can be done such as wrapping or bumping up the temp from 230° to speed things along. 

 

wasn't aiming that comment at anyone in particular, sorry if it came across as such, but it is a comment that people say which usually isn't true but rather the temp. you're looking for (i.e. grate temp.) isn't where the dome thermometer is reading, it's an important distinction.

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If you take an analog (that's not the right word) thermometer (dome thermometer) to extremes, either high heat (most cases) or freezing low (if you live in the north in the winter) the thermometer will eventually get off calibration. If it doesn't have a calibration nut the thermometer is now useless. This has been discussed many, many times before. 

 

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