Ember Mug² Review

A smart mug that warms your coffee

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Ember Mug²

Ember Mug

The Spruce Eats / Cheyenne Elwell

What We Like
  • Warms beverages to preferred temperature

  • Modern minimalist design

  • Customizable LED light

  • 90-minute battery life

  • Easy-to-use app

What We Don't Like
  • Pricey for a mug

  • Interior coating is extremely delicate

  • Hand wash only

Though on the pricier side, the second-generation Ember Mug, the Ember Mug², keeps coffee hot throughout the morning, making it totally worth the investment.


Ember Mug²

Ember Mug

The Spruce Eats / Cheyenne Elwell

We purchased the Ember Mug² so our reviewer could put it to the test. Keep reading for our full product review.

There’s nothing quite like a hot cup of coffee in the morning—something about its warmth is both calming and comforting as you begin the day. Unfortunately, coffee can only stay hot for so long before it quickly loses heat. But finally, there’s a solution: the Ember Mug. 

This smart mug warms hot beverages (whether coffee, tea, or another drink) to maintain the ideal temperature much longer than your average ceramic cup. I tested the second-generation Ember Mug² to see how long it could keep hot liquids warm, how it works with other beverages, and how well the mug and app are designed. Read on to find out what I found.

Design: Modern minimalist

The Ember Mug comes with a sleek matching charging coaster and is made of durable stainless steel with a ceramic-reinforced coating. I found that this coating closely resembled the feel of a ceramic mug and therefore didn’t affect the flavor of beverages like stainless steel can, which was a major plus in my opinion.

I tested the smaller of the Ember Mugs. Weighing 14.5 ounces and measuring 4.2 inches tall x 3.3 inches wide (not including the handle), the 10-ounce Ember Mug is similar in weight and size to a basic ceramic mug, and it charges on its 4.4-inch matching coaster. (The 14-ounce Ember Mug measures 4.6 inches tall and 3.46 inches wide, again with a 4.4-inch coaster.) 

Ember Mug
 The Spruce Eats / Cheyenne Elwell

This product has a minimalist style vaguely reminiscent of today’s smart devices. It comes in either black or white, and both color options feature the Ember logo at the base. Underneath the logo is a smart LED light, which flashes in a solid white to indicate that the perfect temperature has been attained. When fully charged, the LED will turn green, and when the battery is low, the LED will turn red. The power button is located at the bottom of the mug, and overall, I was pleased with the modern look of the unit and found that it fit in well with the rest of my home decor. 

When compared to the first-gen Ember Mug, the Ember Mug² lasts 50 percent longer—now 90 minutes for the 10-ounce option and 80 minutes for the 14-ounce cup—and there’s also an option to select a custom LED color (more on that later).

Underneath the logo is a smart LED light, which flashes in a solid white to indicate that the perfect temperature has been attained.

Setup: Seamless

Prior to using the Ember Mug for the first time, I had to charge the mug by placing it onto its charging coaster, which gets plugged in via the AC power adapter. Once charged (which takes about two hours), the Ember Mug is ready to be paired with a phone. 

To do so, download the Ember app onto your Android or Apple device. The app guided me through the setup process in a step-by-step manner. Then, I simply turned the mug on and poured my beverage of choice inside. 

App: Well-designed and easy to use 

I was able to see and adjust the beverage’s current temperature via the Ember app, which I thought was easy to use and well-designed. When you open the app, a prompt will come up, and all it takes is a single tap to connect to your Ember Mug, which then has a number of personal settings. Since I own two different Ember Mugs (this classic version and the Ember Travel Mug²), I had to select the device I was using at the time to appropriately connect.  

The app took me to a screen with a temperature gauge that changes from a light gray color gradient when the cup is empty to orange, indicating that the cup is in use and has an increased temperature. For future cups, all I had to do was open the app, and the temperature automatically popped up on the screen. Another nice feature of the app is that it notifies you when the ideal temperature has been reached, but of course, the LED light does that, too. 

Ember Mug
  The Spruce Eats / Cheyenne Elwell

Scrolling up on the temperature screen allows you to access preset temperature settings for black tea, green tea, coffee, cappuccinos, and lattes, and tapping one of these options will bring your drink to Ember’s recommended temperature. There’s also an option to create a personalized preset; enter the drink type, temperature preference, and brand (limited options available). The app also has several tea timers for making green, black, and herbal tea, and the app will send you a notification when the tea has finished steeping.

For a more involved use of the Ember app, you can connect it to the health app on your phone. Doing so will allow the Ember app to share information with the health app regarding how much caffeine you’ve been consuming. I haven't had too much luck with this feature yet—there seems to be a delay in communicating the info, so I haven’t been able to see my caffeine intake recorded in the health app.

Performance: Warms mug well 

Out of the box, the Ember Mug is preset to bring drinks to 135 degrees, but you can change this to your preferred temperature, selecting anywhere from 120 to 145 degrees.

I found this to be convenient, as my temperature preference changed depending on the type of drink I made. The app made it simple to adjust the temp if my drink was too hot or too cold, and I often found myself nudging it up after the addition of creamer, which can cool off your drink. 

From the moment I poured my coffee into the mug, it stayed hot until I was finished about 60 minutes later.

This mug excelled at keeping coffee, cocoa, and tea hot throughout the morning. From the moment I poured my coffee into the mug, it stayed hot until I was finished drinking about 60 minutes later. There isn’t a ton of information on how long standard ceramic mugs keep a drink hot, but in my own experience, coffee temperature drops significantly in around 15 to 20 minutes when in a ceramic mug.

Ember Mug
  The Spruce Eats / Cheyenne Elwell

The battery on this 10-ounce smart mug lasted 90 minutes—more than enough time to finish my coffee—though battery life can vary depending on the initial temperature, ambient temperature, and whether or not creamer was added. If you find that you need more time with your morning cup of joe, you can set your mug on the charging coaster to continue charging as you drink.

Features: Adjustable LED and auto shut-off 

As mentioned, one of the updates released with the second-generation Ember Mug is the adjustable LED light. Using the Ember app, I was able to change the LED to my favorite color during setup—I chose pink, but there's a rainbow of hues available.

Another nice feature is that the Ember goes into sleep mode when it’s empty or not in use. That way, you don’t need to keep turning it on and off.

Maintenance: Wash gently and avoid metal utensils

The Ember Mug needs to be hand washed and thoroughly dried before you place it back on the charging coaster. The instructions say it’s submersible up to 1 meter—this is another improvement from the first-generation Ember Mug, which could not be submerged in water at all. 

You’ll want to avoid abrasive cleaners and utensils when washing or using the mug; I found that the bottom interior is extremely delicate. Within the first few days of using my mug, I scratched the bottom of the mug by stirring my coffee with a metal spoon (which is discouraged, according to the quick start guide). The scratches don’t impede the quality of the beverage, but I’m now hesitant to let anything rough or metal touch the bottom of the mug to prevent further damage. 

Within the first few days of using my mug, I scratched the bottom of the mug by stirring my coffee with a metal spoon.

As for the charging coaster, there isn’t much information about care and maintenance. I found that the coaster only occasionally needed to be wiped down with a dry cloth to keep it from collecting dust. I was especially careful to not get the coaster wet to avoid damaging its electrical components. 

Ember offers a 30-day money-back guarantee, assuming the unit was purchased directly from Ember. In addition, there is also a limited one-year warranty for defects in materials and workmanship, and Ember will either repair, replace, or refund a defective product.  

Ember Mug
  The Spruce Eats / Cheyenne Elwell

Price: Worth it if you love hot coffee

In terms of price, the 10-ounce Ember Mug does not run cheap, retailing for around $100. However, it is successful in warming hot beverages to perfection and has the added perks of being easy to use and super stylish. I would say it’s worth the price considering the high-quality design and function, and it would also make a great gift.

Ember Mug vs. Hydro Flask Insulated Coffee Mug 

The Hydro Flask Insulated Coffee Mug is similarly designed to keep beverages warm for long periods of time, but instead of using smart technology like the Ember Mug, it relies on double-wall vacuum insulation to maintain the temperature of its contents. The Hydro Flask Mug comes with a lid and is available in several colors, and it has a slightly larger 12-ounce capacity. 

The two mugs differ slightly in their material makeup, which is important to note, as it can greatly affect the taste of the beverages. Though both are made with durable stainless steel, the Ember Mug has a ceramic-reinforced coating. This might be better for those who prefer drinking out of ceramic mugs versus stainless steel ones, but for those on a budget, the Hydro Flask Mug is only $30. 

Final Verdict

A must-have for coffee lovers.

If you’re a coffee lover who hates the taste of lukewarm java, the Ember Mug² is the solution you’ve been searching for—this second-generation model effectively warms hot beverages with its battery-powered system, and who can resist its sleek, stylish design?


  • Product Name Mug²
  • Product Brand Ember
  • Price $99.95
  • Weight 14.5 oz.
  • Product Dimensions 3.25 x 4.2 in.
  • Color Options White or black
  • Capacity 10 ounces
  • Warranty 1-year limited warranty
  • What's Included Ember Mug, charging coaster, AC power adapter, and quick start guide