If you visit the Tel-Tru Manufacturing web site, there are four models of BBQ thermometers listed for use with Big Green Egg, Primo and Kamado ceramic cookers. Which one should you buy? Here are the four models:
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."What groove, you say? Well, if you look carefully, there is a groove on the stemp which is 1-3/4 inches from the tip of the stem:
We measured the length of stem which extends into our different Big Green Egg cookers and the stem extends between 1-1/2 inches to 1-9/16 inches. In otherwords, 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 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-inch 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.
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.