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Great for grilling, less impressive for running, the ThermaPen by Thermoworks.

Review: Thermoworks ThermaPen

In my quest for an ultra-accurate thermometer for use in extreme conditions, I finally discovered the ThermaPen. With a range from -58F to 572F, it promised to endure long after I expired pathetically on the pavement, and it was advertised as providing virtually instant readings.


I’ve been testing my orange version (naturally) for the last few weeks, and here’s what I discovered.


Great for grilling, less impressive for running.


The ThermaPen is light, although bigger than expected, and is a model of simplicity to use. You open it. That’s it. Pretty straightforward. Once open, the large monochrome reading proves easy to discern in fairly low light (the sauna) and in bright sunshine too.


The device is splashproof (in case you drench it in sweat) and doesn’t seem too frail, although over-extending the probe would break it.


The real test, however, is accuracy and speed. It has the former. And sadly not the latter.


Once it reaches the ambient air temperature, it varies by about 0.5F from time to time, returning quickly to its marker. I conducted the suggested calibration test, dipping it in ice water, and the reading proved to be about 3F off the manufacturer’s claim; 35F instead of 32F. This despite a certificate of calibration. Maybe I did the test wrong, although it’s hard to see how.


The real difficulty is getting the thing to actually settle on a reading at all. In the sauna, ten minutes after opening the probe it was still rising steadily. I spoke to their customer support folks, who told me that the three second reading was for measuring the temperature of meat. This is not clearly marked on their website, and since I had spoken to the sales manager and explained exactly what I needed and why, the recommendation is a little bewildering.


I think with some foresight it will be useful in Death Valley. I’ll leave it out for an hour before I leave for my run, then tape it to my hat with the auto-off function disabled. That way I should get continuous, fairly accurate readings.


This is a very nice piece of equipment but unfortunately it is not entirely suited to the purpose of measuring regular temperatures on a run. As I say, the workaround should do me – but I wish I didn’t have to think that hard about what is billed as the ultimate in thermometers.


Overall Rating: 6/10 – great for grilling, less impressive for running.

Jon Rice
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One comment

  1. Heatrunning:
    Here at Thermoworks we LOVE heat AND Star Wars, so we’re among your fans!

    Quick note on the Thermapen. Try your ice bath again, but this time follow the following five step procedure (it takes some care to get a proper ice bath):
    1. Fill a glass to the absolute rim with ice
    2. Here’s the tricky part: add just enough water to fill in the cracks between the chunks of ice (if you see any ice floating off the bottom of the glass, proceed to step 3)!
    3. Put your hand over the top of the glass and pour out any excess water (your hand might get just bit chilly but its for a good cause)
    4. Let the ice/water mixture sit for about 30 seconds
    5. Insert your Thermapen about two inches into the ice/water mixture and gently STIR it around (Don’t forget to STIR to get an accurate reading).

    Then write back and tell if you don’t get to within 0.7°F of 32° in just a couple seconds. (Who knew making ice water could be so tricky, right??)

    Also, the Thermapen gives accurate readings in more than just meat. In fact that only thing it takes a little longer to get a read on is ambient air temperature since the probe is not inserted into anything.

    And when you see minute changes in the Thermapen reading, keep in mind that that is the actual temperature of something CHANGING or you moving the probe and getting different information.

    Happy desert running!!

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