There have been six models of BBQ thermometers available from Tel-Tru over the years listed for use with Big Green Egg, Primo and Kamado ceramic cookers. Which one should you buy? Here are the six models:

Temp Range		Stem Length
150-750		2.5"
200-1000		2.5"
150-750		3.5"
200-1000		3.5"
150-750		5.0"
200-1000		5.0"

Obviously, the first thing to consider is the temperature range. You may wish to buy one model in each range if, for example, you want to do jerky below 200° and steaks above 750°.

The second consideration has to do with the stem length. Tel-Tru recommends the 2.5-inch stem for the BGE Mini. They recommend the 5.0-stem for all other cookers and sizes. Why? The instructions which come with each thermometer explains:

"For accurate reading, thermometer must be immersed PAST GROOVE on lower portion of stem."

We measured the length of stem which extends into our different Big Green Egg cookers for the 2.5" model and the stem extends between 1-1/2 inches to 1-9/16 inches. In other words, the stem misses the mark by about 3 or 4 sixteenths of an inch. Is this important, you ask. Well, we wouldn't ask the question if we didn't think we have an answer...

We took our six Tel-Tru thermometers and stuck them into various cookers at different temperatures and compared the results. All of the 2.5-inch stem models recorded temperatures within 7% or less of each other. The two 5.0-inch models were within 1.8% of each other. But how did the 2.5-inch and 5.0-inch stem models compare with each other? After we crunched all the numbers, the short-stem thermometers recorded temperatures which were between 13-15% lower than the long-stem thermometers.

What does this mean to you? Well, you want that 2.5" short-stem thermometer so that you don't poke the food with the stem, right? Well, that's ok, but you should understand that the stem on the 2.5" model does not extend far enough into the cooker to give an accurate reading and thus you should add 15% to its reading if you want an accurate reading. Otherwise, you should use either the 3.5" or the 5" models. As of this writing, Tel-Tru no longer lists the 2.5" model on their web page, but if you have any that you purchased from prior years, you should be aware of its limitations.

Another thing that you should be aware of is that the 1000-degree models should only be used above 800 degrees intermittantly. Tel-Tru doesn't really define what "intermittantly" means, but you might want to be aware of this.