Ember TM15 Temperature Control Mug Travel, 3.1 x 3.1 x 8 inches
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Ember TM15 Temperature Control Mug Travel, 3.1 x 3.1 x 8 inches


  • to make sure this fits.

  • temperature range is 120 degree Fahrenheit – 145 degree Fahrenheit

Product information

Manufacturer’s warranty can be requested from customer service. Click here to make a request to customer service.

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June 20, 2017

I have had my Ember mug since November 2016 and absolutely love it, so I was curious about some of the 3 star and lower reviews. Upon reading these, it is clear that a number of purchasers (and potential purchasers) don’t fully understand how the mug actually works. Ember really needs to do a much better job of explaining this (probably with a cute, animated video), but here is what is actually going on:

It looks like many people think that this is a battery operated/heated mug – not an unreasonable asasumption since you do, after all, have to charge the battery. What really happens is much more interesting. Inside the walls of the mug is something that is called a Phase Changer Material (PCM). When I brew a cup of coffee in my Keurig coffee maker directly into the mug, the initial temperature is about 175 degrees with a target of 140 degrees. What the Ember mug does is to extract the heat from the coffee and store it in the PCM. In this case, the material starts out in a waxy form and liquifies as it absorbs heat. This fairly quickly cools the coffee down to the desired temperature, but in the process the PCM becomes a heat storage “battery”. Once the coffee reaches 140 degrees and starts to cool, the mug senses this and extracts heat from the PCM “battery” and uses that to maintain the temperature rather than directly heating the coffee using normal battery power.

If you understand this is how it works, then it is easy to understand why some people are not happy with the battery life. Basically, the hotter the initial temperature, the more storage capacity in the PCM “battery”, and the longer it can maintain the coffee at the desired temperature. My coffee maker at my cabin is a smaller unit that requires me to brew the coffee into a measuring cup and pour it into the Ember mug. I also noticed that the initial temperature there is about 154 degrees. That means that the Ember mug at my cabin can’t maintain my ideal coffee temperature for as long as it does at home because the PCM “battery” is not as fully charged. In fact, one day I got busy and forgot to pour the coffee into the Ember mug until it was just under 140 degrees. Normally I would expect the mug to quickly heat the coffee to the desired 140 degree temperature, but with essentially no PCM “battery” charge, it took longer than usual to get to the desired temperature and I am sure it would not have maintained the temperature for very long.

So, once you understand this, you will realize that want to brew directly into the mug if possible and transfer it to the charger until it is ready to drink if you can do that. If not, as soon as your coffee is brewed, make sure you transfer it into the Ember mug as soon as you can and it will be able maintain the desired temperature for the maximum period of time. If you do this, I think you will find that you will have no issues with how long the Ember mug can maintain the desired temperature. Ember really needs to explain this to customers. In addition to a video on their website, a simple “How Your Ember Mug Works” sheet will go a long way to solving this issue.

A couple of other comments and one suggestion for Ember Mug II. I actually had a problem with the electronics in my original mug. I found that Ember customer support was very responsive and when they couldn’t fix the unit, they quickly sent me a replacement. I also had a problem with the lid in the replacement mug not locking open after a few weeks and they replaced that quickly as well. This is a first generation product so I am pretty tolerant of issues like this as long as the company is responsive, as Ember was.

My suggestion for Ember is to make the next version use wireless induction charging, so there are no issues with the bottom of the mug needing to stay dry to make good contact with the charger.

Enjoy your constant temperature coffee/tea. It really is a completely new experience…

June 17, 2017

Verified Purchase

This mug is shortlisted as one of my Favorite Things, right after my dog. It’s so nice to make a cup of coffee and then get busy doing something else, and when I come back to it my coffee’s still a perfect 140°, right where I left it.

Also of great importance, I was an early backer on their crowdfunding campaign, and when one of their early prototypes failed, they couldn’t have been quicker to replace it. Great people!

Highly recommend!

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October 19, 2017

Verified Purchase

The bottom line
– The mug works perfectly and does what it says it will do and kept my coffee within 2 degrees of my desired temperature the whole time
– I did have an issue and I would give customer service 10 stars if I could for how they handled it

Here is the longer more detailed review

I was frustrated with my coffee being cold half way through drinking it so was intrigued when I learnt of the Ember mug. I had concerns as it was a new company and new technology. I read all the tech reviews I could find and all – yes all of the reviews on Amazon and lots of the reviews on starbucks.
I decided to wait as well let’s be real new tech is going to have issues but when I saw so many positive reviews coming through I decided to try it. I was still expecting that there was a chance I would have an issue but I was comforted by buying it through amazon and by the postive reviews about their customer service and felt any issues would be dealt with satisfactorily.

Well I did have an issue and customer service was everything you want it to be. No excuses, no blame the customer, they were sincere, genuinely wanted to resolve it, incredibly responsive and personal – no cliche copy paste corporate lines.
My issue was one I had not seen anyone else comment on and Ember said they had not heard of it but were very concerned. Basically the lid was too big. You needed to be very strong to screw it on and off and after a few attempts the plastic was wearing off from the friction. We discussed it by email ( note they do not respond on weekends ) and then I shipped it back with the mug at their expense and they sent me a replacement the day after they received it.

My new mug works perfectly. I brewed my coffee into it directly this morning at 140 degree. Within 8 minutes it cooled it to my desired temp of 130 degrees and kept it there within 2 degrees for an hour until I had finished my coffee. I kept the inner lid depressed the whole time as I didn’t want to keep opening and closing it but it still stayed hot as dialed in.
When I first depressed the lid it did spray 5 or 6 drops of crema out but I closed and opened it a couple of more times and it didn’t repeat that. I would be a little cautious the first time and maybe put a napkin over it. It’s possible it was a tad over the max fill line so it may have been user error.

After it kept my coffee hot at 130 degrees OFF the charger plate btw the battery was at 69%.

Other considerations
The mug has pleasing aesthetics. Quite Apple like. It’s simple and graceful. Has a good weight and a pleasing tactile feel. The charger is slim and simple in style too.
The rim is thin. I dislike drinking from thick rimmed mugs so was pleased with this detail.
The 360 degree opening ring to drink out of is also a positive. You don’t have to line up with a hole every time you take a sip.
The lid doesn’t leak! That’s a great feature combined with a quick and easy way to drink from it by just pressing down on the centre ring of the lid. I’ve had soooo many travel mugs leak I had given up on them until Ember came along. It was a big selling feature for me.

There is nothing this mug didn’t do that it said it would and it did everything it said it would.
You may wish it did more but it’s only fair to measure it on what it promises and if you want to get cutting edge technology then realistically be prepared to have an issue but you should demand excellent customer service to rectify and they certainly provide that.

A measure of a company is how well they manage a problem. Two thumbs up to Ember support team!

If you want to enjoy every drop of your coffee at the right temperature without gulping it down all at once I recommend this mug. It’s just made my mornings a whole lot more pleasant 😊

I am attaching a pic of how my first lid fit ( it was too big and sat too high in the mug ) and how my new lid fits – obviously this is before you screw then in place so if your lid seems to fit too tightly this will give you some perspective for comparison.