Tempature Swings ???????

[Turkeyman]

How many degreeHow much of a temp swing do you guys have between the top and bottom rack. It seemed like before I switched my fan to ccw I was within 3 degrees between the top and bottom. Now it's about 7 degrees different.

Thanks,
Scott

[West Coast Kansan]

Well that depends, - dont hate me cause I really dont think there is a true answer - but I have messed around with this temperature thing a quite a bit on my digital 4r just because it gets so much press time.  The "it depends"  kind of goes like this from my experience (I have zero experience with fans so cant comment on those).

At the start, it is huge top to bottom

At the start the difference is bigger with a cold meat load

After a preheat the temp is minimal top to bottom- degree or two (except the back is warmer than the front)

After preheat and your meat goes in - even room temp meats, the difference top to bottom is reestablished 3-7 degrees. But "that depends" on what the meat is and how long you wait to take readings - the drop is almost immediate because you opened the door releasing warm air, the temp difference then reduces fairly quick. Quick "depends", butts will hold a lot of cold, ribs dont hold as much cold and niether does chicken BUT chicken holds lots of moisture that takes energy to warm up so I think it "depends". Also depends in a big way on time you wait between measurements.  Thin lean pieces give up cold and absorb heat faster so a lot depends on time for top to bottom differences. 

After the meat is in for about an hour the difference is about 3 degrees but the back is hotter.

After the meat is smoked about 4 hours the temp difference is minimal with a degree or two but the meat is still having a cooling effect - moisture content as well as a cool hunk of mass

As meat comes up to temperature the difference top to bottom is less but the back side is still warmer a few degrees, because of the air channeling.

The biggest effect is the meat and moisture content. As long as the meat is significantly cooler than tower temperature it will absorb as much heat as it can and the temp difference will be present.

Overall effect of tempature difference top to bottom and mean temperature fluctuations including the non digital control on the digital display units is not worth talking about at the 4 hour point going forward with a front to back and top to bottom rack rotation.

I think the fans are a good idea to the extent they can move heat off the back side above the drip pan. Still reading experiences and learning from experiences posted on the forum and have not tried it yet and dont know. I will put in a fan someday just because it seems to make sense to move heat off the back panel providing a more uniform source of energy.  There was a post earlier about fan direction and I remain confused and cant help.  I think Tom G teased but I agree it has as much to do with the smokers location relative to the equator.  That is still where my head is at...but thought I would throw in what info I have collected.

We are cooking with the energy of a half dozen light bulbs so it is important to be comfortable with low and slow, start early, and use FTC as a buffer to serving, pulling, slicing time.

To collect the data,I fastened my Maverick 72 single probe unit across a wood thread spool and attached the spool to the sides of the unit every few inches by using RTV silicone (comes right off with just enough stick to hold the spool).  Waited between 7 and 30 minutes between readings cause "it depends" on what your doing how long it takes to feel like temps are as static as they are going to get under each condition.  The result is statistically following 4 hours it does not matter and the conclusion is stated in the paragraph above this one.  Not to say its not fun to discuss.

[Turkeyman]

Thanks very much.