Length of stem on themometer - why so important ?

[Guest]

Hi all,

I am intriqued with the threads on the thermometers that you attach to the lid of the WSM. I will most probabally order the Trend #33 as Chris has, but... here's my question.

What is the difference between a themometer with a 4" stem or 2" stem ?

As far as I can see, the temp inside the smoker will be exactly the same 2" away from the top of the lid, or 4" away from the lid.... I can't see the the temp going up 2 more inches down.

So with that said, I wonder what the difference is between them, or why the preference of one over the other ?

Hope this is an intelligent question, I think it is, so here goes

thanks in advance,

Mark.

 

[Mike Rockwood]

I simply stick a Taylor thermometer through the top vent holes in my WSM. I don't know off the top of my head what the length of the stem is, but I do know that depending on what I have inside, the thermometer might touch something and read inaccurate temps.

So, the length would depend on what's cooking inside.

Whatever length you use, you would still need to come an understanding of what the temp difference is between it and the temps your cooking at.

Once I became familiar with the difference between my dome temp and grill temp, I can do without using a probe at the grill. I still calibrate my thermometers/probes every other cook.

Bottom line, it's all in what you are comfortable with, and what pleases you for results.

 

[Guest]

Hi Mike,

ah you mean that the temp up near the top of the dome is that much hotter than the area around the grill ? ... wow... I would never have guessed that.

Do you know offhand what temp diff there is ? would it be as much as 20 degrees ?

anyway interesting.

Mark

 

[Doug D]

It does seem like splitting hairs, but, in fact, temperature readings vary inside the WSM by as much as 20-25 degrees--cooler at the bottom grate, warmer at the top grate and even warmer at the upper part of the dome. So, in theory, 2 inches could be as much as, say 5*. The goal with a lid-mounted thermo, it seems, is to have the longest length stem possible, so you are measuring as close to the actual cooking point as you can but not have it touch the meat on the top grate.

Interestingly, sometimes empirical evidence can suggest otherwise, too. There is an article somewhere on the site, I believe, where Chris once measured temps throughout the cooker that were opposite of the expected.

Bottom line is-- whatever temp you cook at, whatever allowance you have to make in your reading for thermo placement vs. actual meat location-- you just have to get to know your own set-up and try to be consistent from cook to cook.

 

[DaveMcK]

Hey Mark,

I use an 8" probe, candy thermometer thru the lid vent. They come with a clip thing that is supposed to hold the therm to the edge of a pot to monitor your candy temp. If you invert the clip it acts as a handle so you can adjust the probe height and monitior the cooker temp just above the meat your cooking. Real handy, cheap and accurate.
Here is a link to Cris' test of temp differences throughout the cooker.
temp differences

HTH,
Dave

 

[Mike Rockwood]

BBQ Mark - Once you have your thermometers calibrated, you'll know exactly what the difference in temps are, given your setup and a couple of cooks.

I've heard of a number of different differences between the dome, 4inches down, top grate, bottom grate, dry, wet...etc.

Bottom line, understand your setup, know your equipment and enjoy the end product.