Our Honest Review of the ThermoWorks Thermapen ONE Instant-Read Thermometer

Tested by Taylor Murray

The only difference between a perfectly cooked restaurant steak and one you cook at home is technique. Simple tools like a high-quality cast-iron skillet or a decent pair of tongs might seem like the more important tools, but you could be overlooking one key device. An accurate meat thermometer is the best way to achieve a delicious steak, not to mention fish and other proteins. For more delicate items, the temperature can go from just right to overcooked in seconds, which is why you want a thermometer that's not only accurate but fast as well.

Enter the ThermoWorks Thermapen ONE. Over the years, we have tested and loved an array of ThermoWorks products, like the ThermoPop 2 we reviewed earlier this year. We've even tested the Thermapen ONE before, deeming it the best meat thermometer on the market overall. Unlike almost any other thermometer available these days, the main selling point of the Thermapen ONE is that it can read the temperature in just one second. That might seem like overkill given that many much cheaper thermometers can do the same thing in three to five seconds, but that precious time can mean the difference between gorgeous caramel sauce and a pan of blackened mess.

Before we let ourselves get attracted to a flashy gimmick, we thought we'd put the Thermapen ONE through a few tests to see if it could really deliver on its claims and if this is a worthy buy or a one-trick pony.

What Is the Thermapen ONE Thermometer?

ThermoWorks makes dozens of products in both the home and commercial space, from timers to humidity readers. One of the company's newer products is the Thermapen ONE, which claims to be able to get a dead-accurate reading in just one second. This thermometer is handheld and battery-powered, so it can go wherever you need it to. The temperature probe folds flat into the body so that it can be packed flat in a drawer without sticking out awkwardly in any way. It's shockproof, dustproof and waterproof (for up to 30 seconds at a depth of 39 inches). While this durability is great, the thermometer also comes with a five-year warranty.

Reading the display couldn't be easier due to a backlit screen that can rotate 360 degrees, which it does automatically by detecting which direction is up at the time. After a few seconds (the length is adjustable by the user), the screen will go to sleep by itself and can be awakened by simply picking up the thermometer. Older, cheaper models require you to close and open the probe to accomplish this, a two-handed task that you may not be able to pull off if you're wielding tongs or a hot pan.

What's the Difference Between the Thermapan ONE and the Classic Super-Fast Thermapen?

The short answer is that the Thermapen ONE is an improvement on the Classic Super-Fast model in a variety of ways. The primary difference is that the ONE can read a temperature three times faster and 30 percent more accurately, according to the manufacturer.

There are a few smaller differences, such as the ONE boasting a backlight for reading in darker temperatures, complete waterproofing and automatic display rotation. The ONE uses common AAA batteries, whereas the Classic Super-Fast requires harder-to-find CR2032s. Finally, the Thermapen ONE has a sensitive gauge that can detect when you touch it to wake up the display so you don't have to close the probe and reopen each time. A two-year longer warranty period on the ONE doesn't hurt, either.

How We Tested the Thermapen ONE Thermometer

Like all our testing, we started by unboxing the Thermapen ONE and reading through the manuals. After reading the manuals from beginning to end, we assessed whether they were easy to understand and if they covered the important information about operation, cleaning and storage. Once we had thoroughly looked over the thermometer and all the paperwork, we started with the practical tests.

Steak Test: The first test to evaluate the Thermapen ONE involved cooking a simple pan-seared ribeye steak. As the steak came up to temperature, we took readings to see how quickly and accurately the thermometer performed. We also considered how easy and intuitive it was to use and checked if the brand's claim of one-second readings was accurate.

Chicken Test: We repeated the test with a boneless skinless chicken breast. Once the chicken reached 165°F, we took the temperature and marked how long this took and how accurate it was.

Ice Water Test: One of the best ways to check the accuracy of a thermometer is to take the temperature of ice water. The laws of physics dictate that ice water is always 32°F, so we made a bowl of ice water and took the temperature using the Thermapen ONE. During this test, we could see if the thermometer could still maintain its speed and accuracy in colder temperatures.

Boiling Water Test: At sea level, water will always boil at 212°F, so we boiled a pot of water and checked once more to see how accurate the thermometer was. We checked to see if the high heat affected how quickly the thermometer recorded the temperature and if it was accurate.

After each test, we hand-washed the Thermapen One to see how easy it was to clean. We checked to see if the manual had particular cleaning instructions and if the pen was prone to rusting while air-drying on a rack.

What We Think About the Thermapen ONE Thermometer

Performance and Accuracy: After using dozens of thermometers in our test kitchens over the years, we were surprised by the overall performance of this model in particular. While cheap thermometers can take as long as thirty seconds or a minute to settle on a temperature reading, the Thermapen ONE delivers on its promise of readings in a single second. In situations where the thermometer had to read a large temperature swing, the pen took an extra second to give the reading.

When it came to accuracy, the thermometer reported 32°F in ice water and 212°F in boiling water. In other words, perfectly on the money. We also found that the probe nailed the temperatures on the chicken and steak as well, and neither was still raw when it temped to well-done, for example.

Design and Display: The Thermapen ONE builds on the design of previous Thermapens, featuring a handle that houses the display and a long metal probe that rotates out for use and back in for storage. It's currently available in 14 eye-catching colors ranging from hi-vis green to a cool slate blue. The display keeps things simple and streamlined, showing just the temperature without anything else to distract the eye.

Features: For a simple thermometer, the build holds a surprising number of features. The primary appeal of this specific model is one-second readings. There's also a backlit display for easier viewing at a glance. The display goes to sleep after a few minutes to preserve battery life but automatically wakes back up when it detects a pickup. It has a four-way display orientation, so no matter which way you hold it you can get a clear view without having to turn your head. The probe of the thermometer itself is surprisingly thin, which means you don't have to poke a large hole in your steak or chicken to take the temperature. Lastly, the nonslip grip is comfortable to hold and offers enough distance between your hand and the hot pan to not get splattered.

Value: It's not exactly a steal at $109, but this might be the right option for someone who uses a thermometer often and needs accurate readings. If you find yourself cooking delicate food (like pricey fish fillets or tricky sugar work), a thermometer of this quality could save you hundreds over time. For those who rely on precision in the kitchen, the Thermapen ONE's durability and accuracy make it a worthy investment that goes beyond its initial cost. Plus, with quick response times and a sturdy build, it's ideal for the serious home cook or professional who values reliable tools.

Bottom Line: Who Should Buy the Thermapen ONE Thermometer?

If you want to invest in a thermometer that can give you fast, accurate results, you really can't go wrong with the Thermapen ONE. This thermometer solves a lot of issues that you may not even realize are a problem with other thermometers because slow thermometers can ruin recipes if extra care isn't taken. In the long run, this buy could save you hundreds, if not thousands, of dollars over the lifetime of the thermometer. With a five-year warranty, you can bet that it will last you a long time.

Why You Should Trust Our Tester

Taylor Murray is a graduate of Johnson and Wales University with a degree in Culinary Nutrition. She worked as a professional chef for over 10 years before moving into recipe and product testing and development. She has tested several hundred products for Food Network and other brands over the last six years, covering everything from carbon steel pans to food dehydrators.

Why You Should Trust Food Network Shopping Experts

Food Network Shopping Experts believe the best method for testing products is based on how our fans are going to use them in the real world. In each of our Tested and Reviewed stories, products are tested in real home kitchens that reflect real-world use cases. Our testers follow rigorous testing rubrics designed by our expert editors and take copious notes during the testing process. When choosing the best products, our testers evaluate all of the testing data and take into consideration many factors including ease of use, price, product availability and practicality. The products covered on FoodNetwork.com are chosen completely independently by our editors without any outside influence. Our editors do not accept products in exchange for a positive review or promised coverage.