I Can't Stop Drinking Coffee Out of This Temperature-Regulating Mug

The $80 Ember Ceramic Mug keeps 10 ounces of coffee at whatever temperature you want, for as long as you want.
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Ember

My daily coffee routine goes something like this: I arrive at the office, drop my bag next to my desk, grab my mug, and head to the kitchen. I fill it to the brim with the delicious Stumptown brews WIRED provides and bring it back to my desk. Then begins a careful countdown: I have to wait a few minutes for the joe to cool, then drink it as fast as possible before it gets cold. I usually fail, and end up tossing (or begrudgingly chugging) about a third of my mug's contents when I head back for a refill. Rinse and repeat, too many times a day.

Over the last couple of weeks, the Ember Ceramic Mug has changed all of this. The mug keeps 10 ounces of coffee at whatever temperature you want, for as long as you want. You choose the exact temperature in Ember's companion app, or pick from a preset.

Is spending $80 on a mug a ridiculous indulgence, much like $14 avocado toast and those super-expensive candles that supposedly smell like your hometown? Yes. It's also wonderful. See, every beverage has an ideal temperature for consumption. For coffee, science says it's 136 degrees. (Ember defaults to 135, which I guess is a neater number.) It's hot without scalding, and leaves enough room for you to taste the flavors of the coffee rather than simply broiling your taste buds. Ember keeps my coffee exactly right, for hours on end.

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The Ceramic Mug is Ember's second product, after its $150 travel mug. That one has a tiny, integrated screen to display the temperature, which you can control on the mug itself by twisting the bottom. But it only holds 12 ounces of coffee, which isn't enough for any "travel" longer than walking the dog. Plus, $150 is too much even for a coffee addict like me.

The Ceramic Mug's not for travel, of course. It doesn't even have a lid. It's for puttering around the house with that first cuppa, or for keeping your java steamy while you duck in and out of meetings all day at the office. It does feel slightly odd to walk around at work with a crisp white mug, as if I should also be wearing slippers and yawning into the morning sun like the star of a Raisin Bran commercial. The taste still makes it worth it.

Bring the Heat

The technology inside this mug has implications far beyond coffee. You can imagine all the ways it might be applied: in dishware, baby bottles, beer steins. But Ember CEO Clay Alexander decided to start with a mug for a few simple reasons: One, everybody drinks coffee, many of them several times a day. Those people are increasingly willing to spend money to get better coffee. They're already buying burr grinders for their kitchens, Blue Bottle pourovers on the go. And with coffee, Alexander had a perfect way to pitch his product. "We all know how much it sucks to have burning-hot coffee or lukewarm coffee," he says. You can picture the hokey infomercial already.

Heating and cooling things is easy, but doing so uniformly poses a challenge. In his initial tests, Alexander put thermoelectric coolers on a vessel full of liquid, pulling out all the heat energy. But heat rises, and so he'd simply be cooling and re-cooling the same cold liquid while the stuff at the top stayed hot. Eventually, Alexander realized the solution was to create a convection current, like a radiator or a pot of water. So Ember uses cooling and heating elements up the sides of the mug—it activates the highest submerged element, and cools that spot until the cold liquid begins to fall. That displaces hotter liquid, moving it up to the top, where another element on the other side does the same thing. Alexander says even in his early prototypes, he was able to keep the temperature within one degree from top to bottom.

With the help of design firm Ammunition, Alexander turned his ideas into a handsome mug. It was harder than it sounds. "It was a pain in the ass," says Martin Gschwandtl1, an industrial designer at Ammunition. "We can’t make it overly big, or tall, the battery cells in that thing are really big, and they're pretty important in there." Alexander's initial prototypes had lots of buttons and switches, and looked like a gadget. The final product looked like a mug. Other than the one customizable LED light, you'd never know there was tech inside. "We’re not trying to like, reinvent the way you hold a mug handle, and the way you bring it to your face," Alexander says. He likens the approach to Tesla: not reinventing the wheel, figuratively or literally, just embedding technology into a form people understand.

The non-gadgety approach remains one of my favorite features of the Ceramic Mug. Of course, it's not for everyone: Even the coolest $80 mug is still an $80 mug. But if you're a heavy javahead, there's nothing more satisfying than never getting a bad sip.

1UPDATE: This story has been updated to properly attribute Martin Gschwandtl's quote.