cruzmisl Posted July 18, 2009 Report Share Posted July 18, 2009 HI All, I'm doing 25lbs of butts right now and my guru is showing a temp of 255f while my Teltru was showing dome temps of 300f. This was a big discrepancy so I tried moving my guru probe around and it still measures the same. I tried a new TelTru and it too measures close to 300f and this one I calibrated. using boiling water and confirmed it with my Thermapen so I know its right. My feeling is my Guru probe is faulty somehow so what should the dome temps be if I want 250 at the grill? I am also using the upper rack so I'm wondering if I should just keep the dome temp at 250 and not worry what the lower rack temp is. I don't want to overcook the top butt. Thanks, Joe Quote Link to comment Share on other sites More sharing options...
jdbower Posted July 18, 2009 Report Share Posted July 18, 2009 Depending on configuration there can be a bit of a discrepancy between the grate temp and the dome temp. First thing to worry about is placement of your Guru probe. If it's too close to the meat that will bring the effective temperature down significantly, but if it's too close to the edge it may bring the temperature up a but if you're using a heat deflector. The heat flow tends to be along the sides of the cooker and then it gathers in the dome where the temperatures are a bit hotter. BBQ Guru also sells a probe tree that can raise the probes (even Stoker probes ), I would say an ideal location should be about 1/2 the height of the cut. If you're using the main and upper grill maybe hanging the pit probe just under the upper grill would be a good median? Obviously you may also want to try calibrating the Guru pit probe to see if it's close to target. I had moisture get into the plug end of one of my Stoker probes and while it was damp inside it fluctuated between -150F and +1200F - that one was easy to spot... Assuming that the Guru probe checks out and is properly placed then your meat should be cooking at the temperature the Guru probe reports. If not, you can drop the Guru temp until you get the dome temps you want, but this may be reducing the grate temp too much in the process. For me, I ignore the difference between the Stoker temp and the dome temp and I stick with what the Stoker says since it's closer to the level of the meat. But typically I'm only maybe 20-50 degrees off depending on the state of the heat soak. If you're using a food probe to see when the meat is done you don't need to worry about overcooking, it may finish sooner than you expect if the temperatures really are off or later if you correct for an issue that didn't really exist. Quote Link to comment Share on other sites More sharing options...
Conodo12 Posted July 18, 2009 Report Share Posted July 18, 2009 I'll echo Jeff's thoughts and repeat that you should check out the Guru calibration and check your probe placement. Lastly, for all, I highly recommend heat-soaking your KK to alleviate these issues. You will find that a KK brought to temp and heat-soaked for two hours will greatly reduce the temp differences between the power draft controls and the Tel-Tru. Just look at the temp differences at the end of a several hour low and slow. The temps end up being very similar between the Tel-Tru and power draft controls. Quote Link to comment Share on other sites More sharing options...
cruzmisl Posted July 18, 2009 Author Report Share Posted July 18, 2009 Its been going for 12 hours and then the problem suddenly popped up. It was heat soaked I moved the probe around and its withing 10 degrees now. Maybe a combo of probe placement with a TelTru that was a little out of calibration made the problem appear worse than it was. Thanks! PS these butts with the bone take a long time. Quote Link to comment Share on other sites More sharing options...
jdbower Posted July 18, 2009 Report Share Posted July 18, 2009 It also could be a self-perpetuating problem. Every time you open to adjust the probes you let out a lot of heat which first regroups in the dome (creating a large discrepancy) but once you let it sit for a while to type out a forum post the heat has a chance to even out a bit. Why the first blip happened is anyone's guess, it may have even been a quirk of the cool Guru-blown air somehow circulating to the pit probe to reduce the effective temperature. Whatever the reason, glad to see things are back to normal! Quote Link to comment Share on other sites More sharing options...
Firemonkey Posted July 18, 2009 Report Share Posted July 18, 2009 I have also found about a 10 degree difference in the rack level temps vs. the dome temps in a heat soaked grill during a low/slow cook. You can see the probe location in this thread: viewtopic.php?t=1612 There is also some good discussion on this topic in this thread: viewtopic.php?t=2915 Quote Link to comment Share on other sites More sharing options...
