Reviews

Ember Mug Review: A Mug That Keeps Your Coffee Hot for Hours

Dial in your ideal drink temperature, and this smart mug will keep your drink warm to the last drop all morning long.
Lizzy Briskin Avatar
The Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.The Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.The Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.The Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.The Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.The Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.The Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.
Photo: Lizzy Briskin for Bob Vila

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If you’re like many Americans, you enjoy at least one cup of coffee every day, with hot coffee preparations still reigning supreme over iced. Even if you’re more of a tea person, you probably enjoy the first few sips of steaming-hot beverage better than the last cold glug to empty your mug.

The Ember Mug 2 is a smart self-heating coffee cup that aims to do away with the tepid dregs of coffee or tea at the bottom of your cup once and for all. Using a built-in battery and Bluetooth connectivity, the Ember Mug 2 maintains your desired beverage temperature for hours, so every sip is as hot and fresh-tasting as the first.

I’ve been using an Ember mug for years and recently got a second-generation model to test. Now that I’ve tested the Ember Mug 2 for my daily cappuccinos at home for several weeks, here is everything you need to know about these temperature-control smart mugs, including whether they’re worth the price.

Ember Mug 2: At a Glance

The Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.
Photo: Lizzy Briskin for Bob Vila

Rating: 8/10

SPECS

  • Capacity: 10 ounces or 14 ounces
  • Materials: Stainless steel core with food-grade ceramic coating
  • Temperature range: 120 to 145 degrees Fahrenheit

PROS

  • Evenly maintains your desired temperature for hours without fluctuating
  • Bluetooth compatibility means the mug can be controlled from anywhere using a smartphone
  • There’s no wait time for the mug to heat; it starts working as soon as it’s full

CONS

  • Heating element causes your drink to evaporate more quickly than with a regular mug
  • Not dishwasher safe, so it must be cleaned by hand

Get the 14-ounce Ember Mug 2 at:

What is the Ember Mug 2?

The Ember Mug 2 is a Bluetooth-enabled coffee mug with a built-in heater and battery. Through the Ember smartphone app, users can control the precise temperature of their beverage up to 145 degrees Fahrenheit. Once the mug reaches the desired temp, it holds steady so the coffee or tea is always perfectly heated.

The mug has a stainless steel core with a food-grade ceramic matte or metallic coating. It charges by simply resting on the included charging coaster. Keeping the mug continuously warm causes liquid to evaporate faster, but for those who like to keep hot drinks hot, it’s exceptionally good at holding temperature as long as the coaster is charged.

Setting Up the Ember Mug 2

This mug is pretty much ready to use straight out of the box. Cleaning the cup and pairing it with my phone via Bluetooth took just a few minutes. I downloaded the Ember app and selected my desired temperature. The smart mug will remember the preferred temperature selection for future fill-ups, but it can always be changed.

One caveat is that the Ember 2 may need to charge for a short while before it’s ready. Users can still drink from the mug but must keep it on the charging coaster between sips to maintain a steady battery. Once the light on the front of the mug turns green, it’s fully charged.

The Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.The Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.The Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.The Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.The Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.
Photo: Lizzy Briskin for Bob Vila

Using the Ember Mug 2

The Ember Mug 2 comes in two sizes: 10 ounces and 14 ounces. The 14-ounce mug is closer to a standard coffee mug and feels more substantial. It’s a better size for tea and drip coffee drinkers, as it holds more liquid. The smaller mug is slightly less expensive and a good size for most single-shot espresso-based drinks, such as cappuccinos or lattes.

The Ember is made from stainless steel covered in a smooth, nonstick ceramic coating. It comes in a variety of colors, including neutrals and a pretty sage green color. Ember also makes a premium metallic collection.

The Ember mug is more bottom-heavy than a typical coffee cup to accommodate the battery and heating element. It comes with a matching coaster that doubles as the charger. The charger has a 6-foot-long cord, giving users enough space not to feel tethered to an electrical outlet.

It’s important to note that the mug should not be used with metal utensils, which can cause chips and scratches in the ceramic coating. It’s also not dishwasher-safe, though it is water-resistant and can be submerged up to 1 meter. The best way to wash it is with warm, soapy water.

The mug charges via a set of metal rings embedded in the bottom. It’s important not to place the mug on its charger when the bottom is wet; this can corrode the battery probes on the charger, and eventually, they’ll stop working. I had this experience with my first Ember mug and had to get a replacement coaster.

Does the Ember Mug 2 keep drinks hot?

The Ember Mug 2 excels at its central job: keeping liquid hot. As long as I maintained a connection between the mug and my iPhone via Bluetooth while the mug was full, my coffee’s temperature never fluctuated from the exact temperature I selected.

I generally start with coffee that’s already close to my desired temperature, so I don’t usually rely on the mug to heat my drink from cold. Ember’s support page does not recommend using it to reheat cold beverages, as the mug may be unable to detect the liquid and could read as empty as a result.

Speaking of the battery, the Ember 2 has a longer battery life than earlier iterations of the mug, but it doesn’t last forever. As long as I keep the cup charging on its coaster overnight, the battery lasts long enough to keep my coffee hot in the morning—about 80 minutes for my 14-ounce mug. For the 10-ounce mug, the battery keeps drinks hot for about 90 minutes. Slow sippers can buy a second coaster to avoid losing power.

In addition to a shorter battery life, my original Ember Mug also often had connectivity issues. Ideally, it should automatically connect and remember the set temperature preference, never requiring users to go back into the app for setup. However, when the mug loses connection to the app, the heating element turns off, requiring users to pair it again to re-establish heating. The Ember Mug 2 is better at maintaining this connection than the earlier model, but I have had to reconnect two or three times over a month of use.

It’s also worth noting that drinks tend to evaporate faster with an Ember mug than with a standard ceramic cup, thanks to the heater. I typically finish my cup in around 30 minutes, so I don’t notice the increased evaporation. However, slower sippers will want to keep an eye on the contents of their mug should they not want to be met with an empty cup. The heater automatically turns off when the cup is empty, so at least there’s no danger of overheating.

If all the liquid does evaporate, however, it can make the Ember harder to clean. I have also noticed this if I leave unfinished liquid in the mug, especially if the drink contained dairy. Anytime I failed to clean the mug right away or let my drink evaporate down to nothing, it left a sticky film on the ceramic that took some elbow grease to remove.

Ember The Ember Mug 2 in sage green on a kitchen counter on its pluggedThe Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.The Ember Mug 2 in sage green on a kitchen counter on its plugged-in charging coaster.-in charging coaster.Mug 2 Review
Photo: Lizzy Briskin for Bob Vila

Worth the Price if You Love Hot Coffee 

This mug is certainly more expensive than a typical coffee cup, but now that I’ve used it for years, I can say with confidence that with the Ember 2, you get what you pay for. The transparency of temperature and ability to dial in your precise preference for a drink you enjoy every morning makes this mug worth the price tag.

As long as you don’t put it on the charger wet, run it through the dishwasher, or use metal spoons to stir your drink, the Ember Mug 2 will last for years.

Is the Ember Mug 2 right for you?

If you regularly drink hot beverages and like keeping them hot, the Ember Mug 2 is a great solution. It also makes a thoughtful gift for the coffee or tea drinker in your life. Though you’ll need to sacrifice some counter space for the charging coaster and the mug is hand-wash only, it does its job well and is comfortable to hold and easy to use. The mug comes in a range of color options to match your kitchen aesthetic and will last for years as long as it’s treated properly.

Where to Buy the Ember Mug 2

Get the 14-ounce Ember Mug 2 at:

Meet the Tester

Lizzy Briskin is a trained chef, writer, and avid home cook. She has over 7 years of experience in the food industry including as a food editor at Real Simple, Food Network, and Pioneer Woman Magazines. She contributes to Wirecutter, The Kitchn, Apartment Therapy, and Simply Recipes. Living in NYC, she savors every piping-hot sip of her daily cappuccino.

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Lizzy Briskin Avatar

Lizzy Briskin

Contributing Writer and Editor

Lizzy is a trained chef, writer, and product reviewer with over 6 years of experience in the industry. She has contributed to BobVila.com since 2022 and focuses on kitchen, cooking, and home products and projects.

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