Installing a Thermometer - What size probe?

[Mike in MD]

I plan on installing a thermometer in the dome of my WSM opposite the vent (Trend, Tru-temp, etc). What length probe do you recommend, a 2.5, 4, or 6 inch? Does it matter?

 

[Doug D]

Too long and you risk it touching the meat in certain situations, too short and its reading may be affected by its proximity to the vent. Split the difference and 4" sounds about right.

 

[John Mason]

I installed two Tel-tru therms one just above the bottom grate and one in the lid just above the top grate. The first one I bought was a 4" stem - it took up too much room, so I traded it in and got two with the 2.5" stem.

I was a bit worried that the tip would sit in the heat flow between the water pan and the side of the WSM and give high readings, but it just extends past the lip of the water pan about an inch or so and gives fairly accurate readings unless I fill the WSM up with too much meat. If the meat sits too close to the stem tip then I get false low readings.

With the 18" diameter of the WSM, a 4" therm stem just seems to me to extend too far. You'd have to be careful very time you set the lid down that you weren't touching the meat and on a lower grate mounting you'd have trouble removing the lower grate with the stem sticking out (in) so far.

Just my thoughts on the subject.

 

[Doug D]

I avoided both issues-- touching food and heat flow around pan-- by inserting my 6" stem thermo thru an upper bolt-hole just below the top grate.