My coffee routine is needlessly detailed, but fairly predictable. I wander blearily into the kitchen, add some water to the kettle, and start heating it to 200 degrees Fahrenheit, grind some coffee beans, get out the Chemex, add and rinse a modern filter, put everything on the scale, add 40 grams of beans, slowly pour in 600 milliliters of heated water, pour it into my trusty silver Yeti Rambler, and head to the living room to either play with my son or watch TikTok on my phone. That’s life, you know?
Over the past few weeks, Ember Tumbler has crept into this routine. Mug for $199 It’s Ember’s newest product, but it carries the same promise as the company’s popular mugs: It can keep your drink exactly the temperature you want it to be, for hours. Its internal heating system will keep your drinks at 135 degrees Fahrenheit by default, but if you pair it with your phone via Bluetooth, you can apply the Ember app to set it exactly how you like it.
The Ember mug was element of my life for a long time, even though two things drove me nuts. It only held 10 ounces of fluid — objectively, not enough, but thankfully there’s now a 14-ounce model — and it was a standard cup with a handle, so I couldn’t take it on the train or in the car. (Ember’s first product was actually a travel mug, but it only held 10 ounces. What are we doing here, people?)
First, I poured boiling water into both cups and after about 60 seconds (that’s how long it took to find the thermometer) I measured the temperature in both. That was our control number.
- Rambler Starting Temperature: 205.9 degrees Fahrenheit
- Initial drum temperature: 204.6 degrees Fahrenheit
Then I put lids on both cups, closed them, and left them for an hour. This is the “I made coffee and then something jumped out” test. Then I measured their temperatures again.
- Rambler after hour: 180.7 degrees Fahrenheit
- Tumbler after one hour: 149.4 degrees Fahrenheit
Pros and cons. The Rambler holds heat better, but the Tumbler’s job is to nippy my drink to the perfect drinking temperature – you can set any temperature you want in the Ember app on your phone, but it defaults to 135 degrees Fahrenheit, which science (the Ember app) tells me is the ideal drinking temperature for coffee, and then uses internal heating elements to maintain that temperature. So a quick drop isn’t necessarily a sign that there is a problem.
Then I opened the mouthpiece of each lid and left them for another hour. This is the “early morning meeting” test.
- Rambler after two hours: 162.7 degrees Fahrenheit
- Tumbler after two hours: 139.2 degrees Fahrenheit
Same! The double-insulated Rambler still keeps you sultry, but the Tumbler is at the perfect drinking temperature after two hours. Everyone wins.
In the third hour, I upped the ante. With lids on and spouts open, I exposed both cups to the breezy 40-degree Fahrenheit of my morning. This is the “heated drink on a icy day” test.
- Rambler after three hours: 144.1 degrees Fahrenheit
- Tumbler after three hours: 135.1 degrees Fahrenheit
Once again, I call this a double win. Both lose heat—it’s tough stuff!—but they still do their job, and the Tumbler is still in its sweet spot. After three hours, both of my drinks are still drinkable.
After three hours both of my drinks are still very drinkable
I brought both cups inside, closed their spouts, and left them for another hour. This is a test of “maybe this has just become my afternoon coffee.”
- Rambler after four hours: 135.0 degrees Fahrenheit
- Tumbler after four hours: 113.7 degrees Fahrenheit
For once, we have a drink that is too icy, and that is the Tumbler. The battery died just at the end of the third hour, as advertised, and now, without a heater and without insulation, it is starting to lose temperature quickly. Meanwhile, the Rambler is still holding up.
My last test involved leaving them overnight, which isn’t exactly a real-world apply case, but hey, I’ve already poured out all the water. I call this the “left it overnight” test.
- Rambler after 12 hours: 99.0 degrees Fahrenheit
- Tumbler after 12 hours: 76.5 degrees Fahrenheit
Of course, both are undrinkable here, but once again, the Rambler does a noticeably better job of keeping my drink sultry. The Tumbler is, for all intents and purposes, room temperature.
These tests confirmed two things for me. First, the Tumbler does a great job of quickly heating a drink to the right temperature and keeping it there for hours. Points for that elegant mug! But second, if my goal is to keep my coffee heated and drinkable (sometimes too heated!) for as long as possible, the Yeti mug is definitely the better choice.
Comedian Brian Regan has a great scene where he walks through an appliance store looking for a refrigerator. “This will keep all your food icy for $600,” the salesman tells him. “You’ve got This refrigerator, keeps all your food icy for $800.” Then the salesman goes to the next one, puts his arm around her and starts saying, “Look at this: $1,400, keeps all your food icy.”
That’s how I feel about the Ember Tumbler. It does its job, which in this case is to keep all my drinks sultry. But the 16-ounce Yeti Rambler costs $30, compared to $200 for the Tumbler, and it actually keeps my coffee above the too-cold mark for longer. And if I need it to nippy down faster, I can just remove the lid or throw in an ice cube. I’m much more concerned with keeping my drink sultry than cooling it down faster.
If you spend most of your time, like I do, going from the kitchen to the basement, and the charger is no more than a room away, the Tumbler is great—when I leave it on the charger, my coffee stays at or near that magical 135 degrees Fahrenheit all day long. It’s a great mug, though ridiculously high-priced considering my microwave is right upstairs. But when I leave the house, I take the Rambler. Thirty bucks, it keeps all my drinks heated.
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