If you're looking at purchasing an Ember Mug or you've already got one you may be wondering what temperature range the Ember Mug has and how hot it can heat your tea or coffee to.
The Ember Mug ranges from 120-145ºF (48.9-62.8ºC) and will not heat liquid that is below 100ºF (37.8ºC). The limited temperature range is idea for expensive coffee and ensures the heating element doesn't burn the your drink and make it bitter.
The Ember Mug is designed to maintain temperature and isn't very good at actively warming things up. It takes around 30-40 minutes to heat up a cold drink and this will use the entire battery of the Ember Mug.
When you first purchase an Ember Mug it will be set to the default temperature of 135ºF (57.2ºC) which is the ideal drinking temperature for a latte/
Why Doesn't The Ember Mug Go Any Hotter?
Ember Mug are expensive coffee mugs and they are predominantly designed for expensive coffee drinkers. People who spend $5-$10 on their barista made coffee are likely willing to invest in a mug to keep it at the right temperature down to the last sip.
Studies have shown that the ideal drinking temperature for coffee is between 130-145ºF (55-62ºC) which *shock horror* is almost exactly the heating temperature range Ember Mugs work at.
Going above 150-158ºF (65-70ºC) for an extended period of time you start to burn both the coffee as well as the milk and this can lead to the milk curdling in your drink due to a break down of the proteins.
In this podcast interview with Ember founder Clay Alexander I think he gives a really good summary of why the Ember Mug doesn't go any hotter and also why it doesn't heat up your drink quickly.
So at Ember, we're all about precision temperature control…we like to talk about how we do gentle warming. So what we do is we spread the surface area of our heating elements around to a larger surface area. And that allows us to lower the surface temperature of where the heater is, and so that we can gently warm the coffee or tea, which does not burn the molecules.
When you're in a carafe or any of these other type heaters. You're actually burning the molecules of the coffee. And that's why after 20-30 minutes, it starts to taste bitter.
So to get into Starbucks, we actually had to go through a whole bunch of scientists at Starbucks that are coffee tasting scientists that had to test the crap out of this stuff on does it derogate the flavor over the time that you're drinking out of it? And the answer is no, it does not. And that's how we got into Starbucks.
So as you can see Ember Mugs are limited in their heating ability due to a conscious choice to preserve the quality flavor of your drink. It's not because they couldn't make a mug that heated up drinks even hotter.
I'm very confident that Ember could have made a coffee mug that brought your drink to boil. In fact there are Ember Mug alternatives that are able to do this quite easily. But instead, Ember focused on a premium drinking experience and giving you the best tasting (and best temperature) coffee or tea possible.
Can The Ember Mug Be Used To Heat Up Cold Drinks
While the Ember Mug can technically be used to heat up cold drinks it's extremely impractical and takes a very long time and drains almost all the battery life.
Below is a video of mine where I tried to heat up cold coffee. It took around 40 minutes and the mug kept turning off or saying it was empty when the drink was under 100ºF (37.8ºC).
So while it is possible it isn't really worth the time and effort and battery life, especially if your drink is under 100ºF (37.8ºC).
You're better off putting your drink in a regular ceramic mug and heating it up in the microwave and then putting it in your Ember Mug to maintain the temperature. Just make sure you don't put your Ember Mug in the microwave as this is extremely likely to break the mug completely.
What Is The Best Temperature For Coffee In My Ember Mug
A lot of people have a lot of different opinions on the perfect temperature that coffee should be drunk at. Ultimately it comes down to personal preference but what do the experts say are ideal temperatures for your Latte, Flat White, Cappuccino or Long Black?
I used to work in an espresso bar and with any milk based coffees we would heat the milk to around 130ºF (55ºC). If someone ordered “extra hot” then we would heat the milk to around 140ºF (60ºC).
For plant based milks like soy and almond milk we wouldn't even go this hot as it could cause the milk to curdle and separate as they don't have as many proteins as dairy milk. Oat milk seems to hold up better than soy and almond when it comes to the higher temperatures.
Going above these temperature can cause a break down in the proteins in the milk and cause it to separate and curdle. While this is still perfectly safe to drink the texture is not as nice and it often leads to the coffee tasting more bitter.
Even a long black left on high heat for too long will degrade the flavor of the coffee and over time the coffee with become more and more bitter.
What Is The Best Temperature For Tea In My Ember Mug?
Different types of teas are designed to be brewed (or steeped) at different temperatures. The above infographic from Let's Drink Tea shows that while Rooibus tea should be brewed almost at boiling temperature herbal teas like Hibiscus should be brewed much colder around 158-165ºF (70-75ºC).
However, when it comes to drinking tea no one wants to drink tea this hot, it'll burn your mouth. So how hot should you drink your tea?
Ultimately it comes down to personal preference.
If you have milk in it then the same rules that apply to coffee apply to tea. Try to keep it below 140ºF (60ºC) and for most people around 130ºF (55ºC) will be the ideal drinking temperature.