Probably the most frequently asked question about using MEATER products is "Why is the ambient temperature of my MEATER different to the reading on my oven/grill?"

What MEATER Says About The Ambient Temperature Sensor

First of all, let's look at what MEATER has to say on this topic in the FAQ on their web page:

"MEATER measures the ambient temperature directly at the black ceramic tip. Since most cooking appliances tend to have hot and cold spots, we designed our ambient sensor to be extremely sensitive to microclimates within the appliance, so that our probe can detect the temperature that your food is actually being exposed to. Because of these hot/cold spots, the reading can vary greatly depending on the location of the probe.

This is important to take into account when trying to compare the reading with another thermometer or a second MEATER probe, even a few inches away. Additionally, proximity to the colder meat itself can affect the ambient reading.

If you’re measuring against a built-in thermometer in your cooker, these tend to read either the average overall temperature or just the temperature right near the lid, and this will often be different from the temperature immediately surrounding the meat."

The Influence Of Cold Meat

The MEATER's ambient probe is located near in the black ceramic handle. This places it close to the meat. The temperature of the air near the cold meat is going to be lower than elsewhere in your cooker. And as the temperature of the meat rises during the cook, so will the temperature of the air near the meat. This is why the MEATER's ambient readings rise during the course of the cook.

The Influence Of Evaporating Moisture

In addition to the fact that the meat itself is colder than the cooker's ambient temperature, there is also the fact that moisture is evaporating from the surface of the meat. This evaporation also serves to lower the temperature of the air close to the meat. As the meat cooks and the amount of moisture evaporating from the surface of the meat reduces, the cooling effect of the evaporation also reduces. This also contributes to the MEATER's ambient readings rising during the course of the cook.

Two Locations, Two Temperatures

First of all, we'll state the obvious. If you take a temperature reading in two different locations, you ARE going to get two different readings. Don't be fooled into thinking that somehow your cooker's temperature is relatively uniform. It isn't. We conducted an experiment on our large Big Green Egg and found that the temperature in two locations only 1 inch apart varied by up to 40°F.

Using The MEATER's Ambient Reading To Control Your Cooker

We think this should be obvious, but you can't really use the MEATER's ambient reading to control your cooker. The Ambient reading changes over time even though the cooker's temperature remains constant. This is due to the influence of the meat's temperature on the MEATER's ambient probe. Typically the ambient reading starts low and increases over the first hour or two of your cook, again despite the cooker's temperature remaining constant. If you keep the MEATER's ambient temperature constant, your cooker's temperature is going to be dropping.

So What Is The Actual Purpose Of The MEATER's Ambient Probe?

If you dig into the Apption Labs patent application and look at paragraph 46:

As noted above, more accurate predictions on completion time and resting temperature rise can ordinarily be made by utilizing dual-sensor technology. Using an ambient or external thermal sensor in or near the third portion 102 [location of the ambient probe] can enhance estimation of heat input at the location of the food 108, which can vary when the food 108 is moved, turned, or when changes in cooking environment occur, such as opening the hood of a BBQ, adjusting heat on a gas grill, or charcoal fuel losing heat. The heat input at the location of the food 108 can be estimated more accurately using an ambient or external thermal sensor adjacent an exterior surface of the food 108 and measuring the ambient temperature over a period of time."