Instant-Read Thermometers

Published March 2016

How we tested

ThermoWorks recently released an updated version of our favorite instant-read thermometer, the Splash-Proof Super-Fast Thermapen. The new model, called the Thermapen Mk4 (Mark 4), is almost identical to the older model in shape, size, and weight, but has a number of additional features: New sensors allow the display to automatically rotate, wake up, turn off, and illuminate in darker conditions. The Mk4 is more water resistant than the older model and uses a single cheaper, more common AAA alkaline battery instead of the two lithium batteries previously used. ThermoWorks says that as a consequence of the switch, battery life has doubled from 1,500 hours to 3,000. 

The Mk4 is sold for $99; ThermoWorks plans to keep selling the older model, now called the Classic Splash-Proof Thermapen, for $79. Curious to see if the improvements were worth having, we bought four Mk4s and tested them against the Classic, using them to take the temperatures of an ice bath and boiling water (to test their accuracy), roast chicken breasts, and caramel sauce; submerging an Mk4 in an 8-quart container of water for half an hour; and having both right-handed and left-handed cooks operate them. We found little difference between the two models in terms of accuracy or speed; both were very precise and read out correct temperatures in 2 to 3 seconds. (One of the Mk4s failed to turn on consistently, so we ordered five additional units to make sure that the problem wasn’t systemic. We’ll continue to monitor their performance, but so far, all the other units have worked great.)


Which Thermapen should you get? While you can’t go wrong with the Classic—our old, reliable favorite, now cheaper than ever before—in the end, we think the Mk4 has a slight edge because of its additional features. The rotating display does make it easier to read the temperature in any position, although it’s a stretch to say that the new Thermapen is therefore as ambidextrous as ThermoWorks claims—the handle is still built for righties, and while the display rotates 360 degrees, the probe itself doesn’t, meaning lefties can’t operate the thermometer at oblique angles.

The extra waterproofing protects the thermometer against more than the occasional splash, ensuring that it’ll survive an accidental drop into a sink full of water, and the backlight made it helpful for grilling at night. Testers particularly liked the new model’s motion sensor-activated automatic sleep/wake function, which means that as long as the probe is out, the thermometer turns on the moment you pick it up; the Classic automatically turns off after 10 minutes, forcing you to close and reopen it when you want it to wake up again. It’s too soon to tell whether the Mk4’s battery life is truly twice as long as the Classic’s, but we’ll keep tabs on the new model in the kitchen and report our findings.

Try All Access Membership Free for 14 Days

Included in your trial membership

  • 25 years of Cook's Illustrated, Cook's Country, and America's Test Kitchen foolproof recipes
  • In-depth videos of recipes and cooking techniques
  • SAVE all your Favorites for easy access
  • Up-to-Date reviews and product buying guides

Get America's Test Kitchen All Access — become the Smartest Cook you know, guaranteed.

Email is required
How we use your email address

The Results


Design Trifecta 360 Knife Block

Admittedly expensive, this handsome block certainly seemed to live up to its billing as “the last knife block you ever have to buy.” The heaviest model in our testing, this block was ultrastable, and its durable bamboo exterior was a breeze to clean. Well-placed medium-strength magnets made it easy to attach all our knives, and a rotating base gave us quick access to them. One tiny quibble: The blade of our 12-inch slicing knife stuck out a little.


Schmidt Brothers Downtown Block

This roomy block completely sheathed our entire winning knife set using just one of its two sides—and quite securely, thanks to long, medium-strength magnet bars. Heavy, with a grippy base, this block was very stable. An acrylic guard made this model extra-safe but also made it a little trickier to insert knives and to clean; the wood block itself showed some minor cosmetic scratching during use.


Schmidt Brothers Midtown Block

This smaller version of the Downtown Block secured all our knives nicely, though the blade of the slicing knife stuck out a bit. With a base lined with grippy material, this block was very stable. An acrylic guard afforded extra protection against contact with blades but made it a little harder to insert knives and to clean; the wood itself got a little scratched during use.

Recommended with Reservations

Swissmar Bamboo Magnetic Knife Block

This small, scratch-resistant model had a stable, rubber-lined base and could hold all our knives, though the blade of the 12-inch slicing knife stuck out a bit. But inch-long gaps between its small magnets made coverage uneven and forced us to find the magnetic hot spots in order to secure the knives. Its acrylic guard made it safer to use but harder to insert knives and to clean.

Not Recommended

Messermeister Walnut Magnet Block

This handsome block was done in by its shape—a tippy, top-heavy quarter-circle that wasn’t tall or broad enough to keep the blades of three knives from poking out. It lacked a nonslip base, and its extra-strong magnets made it unnerving to attach or remove our heavy cleaver. Finally, it got a bit scratched after extensive use.


Epicurean Standing Knife Rack 12"

This magnetic block sheathed all our knives completely, though with a bit of crowding. But it was hard to insert each knife without hitting the block’s decorative slats on way down, and because the block was light and narrow, it wobbled when bumped. Worse, we couldn’t take it apart, so splatters that hit the interior were there to stay. Additionally, the outside stained easily, and when we wiped it down, the unit smelled like wet dog.


Kapoosh Rondelle Knife Block

This model stabilized knives with a mass of stiff, spaghetti-like bristles that shed and nicked easily after extensive use, covering our knives with plastic debris. While all our knives fit securely, several of the blades stuck out, making this unit feel less safe overall. Finally, though the bristles could be removed and cleaned in the dishwasher, their nooks and crannies made this block hard to wash by hand.


Kuhn Rikon Vision Knife Block, Clear

This plastic block required us to aim each knife into the folds of an accordion-pleated insert that was removable for easy cleaning but got nicked easily with repeated use. Because we could only insert the knives vertically, longer knife blades stuck out; a cleaver was too wide to fit. The lightest model in our lineup, this block was dangerously top-heavy when loaded with knives.