Have you ever noticed that there is a thermometer sticking out the top of your smoker or grill? Have you ever wondered what it’s good for?
Most people just accept that the number on their dome thermometer represents the internal cooking temperature of their grill or smoker—like the digital readout on an oven.
But here are a few things to consider…
1. The quality (and therefore the accuracy) of the “dome” thermometers that ship with almost all smokers and grills, even very high quality smokers and grills, is usually very poor. This dial thermometer is an afterthought, typically sourced from the Far East.
2. Almost all of these “dome thermometers” have bi-metal probes with springs inside of them made of two metals that expand at different rates pushing the needle on the display. Physical shocks can knock these metals out of alignment, which can happen time and again when you close the lid of your grill or smoker quickly.
3. Recalibrating a dome thermometer that is frequently out of alignment can be tiresome and difficult even if there is an adjustment nut provided (on many such thermometers there is no way to recalibrate).
4. Even if your dome thermometer WERE calibrated OR accurate it would STILL just be averaging the temperature of the air at the very top of your smoker or grill, not the temperature of the air down where the action is. Anyone familiar with convection currents knows that there can be radically different temperatures in different zones of the same smoker or grill—as much as 50°F.
5. Cold air rushing in from outside when you open your smoker or grill to check your food can drop the temperature of the air in the dome relative to the cooking temperature near the grill.
6. Warm air reflected upward by a deflector plate or drip pan up along the sides of your smoker or grill can likewise raise the temperature of the air in the dome relative to the cooking temperature near the grilling surface.
The simple truth is, if you are using dome temperature as reflected by the standard dome thermometer on your smoker or grill as a gauge of the cooking temperature of your food, you could be off by as much as 50°F in either direction, too hot or too cold!!
Think that could impact the quality of your steaks??
(Let alone your results with longer cooks like ribs or turkeys.)
Don’t overcook your food by relying on faulty measurements!
Measure the air temperature of your smoker or grill where the food is actually being cooked!
Here’s what we recommend:
Key 1: Suspend the tip of the probe measuring your internal air temperature about 1” above the grill surface that will actually cook your food.
Key 2: This can be accomplished using…
a. probe clips that can accompany some cable probes
b. binder clips or other kinds of clips from the office store or hardware store OR
c. a ball of tin foil (our favorite)
The tin foil method is the one preferred by many professional BBQ teams. To do this, simply crumple tin foil around your air temp probe so that it protrudes 2 to 3” beyond the foil and so that the ball of foil, resting on the smoker or grill grate, places the probe tip about 1” from the grilling surface.
The great thing about this method is that you can reshape the foil ball as needed during the cook. You can even move it around with a pair of tongs (remember not to touch it with your fingers!).
Key 3: Use a thermocouple probe with an industrial quality cable.
Thermometers sold for home BBQ or oven cooking often employ lower quality thermistor probes with limited ranges and limited moisture sealing, not to mention less accuracy. Consumer cooking alarms suffer from a very high rate of probe failure in BBQ use due to their proximity to flames and hot coals. BBQ cookers are also very humid environments. Moisture is the other most common reason for probe failure. While higher quality thermistor probes (like in our top rated ChefAlarm) can be more accurate and more durable in the demanding environment of grills and smokers, most BBQ professionals prefer to use professional thermocouples built for the commercial smokehouse industry at higher temperatures.
Key 4: You’ll also need an instrument capable of processing thermocouple probe readings….
The new ThermoWorks ThermaQ reads two commercial thermocouples: one probe can be used in the food, with an alarm setting, and the second probe can be used to read the grill or smoker air temperature where the food is located. Over time, you will spend less on probes by using the professional probe solution from the start. Thermocouples also come in a greater variety of probe types that allow many different measurement solutions.
So what should you do with that dial thermometer in your dome? We recommend leaving it in place. It looks nice and it fills the hole! Just don’t depend on it to measure the internal temperature of your grill or smoker.
When you’re cooking, read the temperature next to the food. After the temperature of the food itself, that’s what really matters.