Some tech companies are focused on global problems like reversing climate change or providing internet access to developing areas. Others, meanwhile, prefer to stick to an all-American dilemma like "why is my freakin' coffee always either too hot or too cold?" The Ember temperature-regulating coffee thermos may be the ultimate example of a first-world-problem product, but it also represents a smart, simple and practical idea executed brilliantly.

CES is famous for showcasing products that are either copycats of something we already have or solutions in search of a problem. While passing by Ember's table, though, the tall and black mug struck me as a truly-fresh idea that solves a real (though Seinfeldishly-petty) problem. I've told several fellow coffee devotees about the idea of a thermos that maintains a chosen temperature for your java, and their eyes all lit up immediately. The only question was "does it work?"

Ember works. After pouring your brew into the 12-oz. thermos, it will show you the coffee's current temp on the hidden display that appears to magically light up from the bottom section of the product. Twist the bottom of the mug to choose your ideal temperature, and within a few minutes it will either heat or cool your drink to sustain your chosen level.

In my experience, it works exactly as advertised: Setting it to higher temps yields a hotter cup of coffee, while lower settings quickly cool it off (the company describes a phase-change cooling system around the stainless-steel interior lining that lowers temps).

Most importantly, keeping your coffee at your ideal temp can make your cup taste better all the way to the end (I'm no stranger to coffee that starts great and ends not-so-great).

If you prefer, you can instead set the temperature in a companion smartphone app (available for iOS and Android), and optionally receive a notification when your coffee hits its target.

Unlike most travel mugs I've used, you can drink from any side of Ember's lid: It uses a pop-in mechanism that opens or closes the chasm between you and your beloved java with a quick press (it will successfully adjust the temp either way).

While the lid is dishwasher-safe, the mug itself isn't. If you don't already have one, you'll want to pick up a long bottle brush that, while hand-washing, lets you rid the steel interior of residue from previous fills.

The mug includes a wireless charging stand that juices up the thermos by simply resting it on top.

Battery life is good enough, but not great. Ember lists it as "up to two hours," which lines up closely with our experience. While that should be enough time for one mug, those who want to use Ember for multiple fills in the office will want to either bring along the bundled charging stand or order a second one from the company's website for US$40.

With a battery and other tech inside, the mug is a hair taller than many standard travel thermoses: It's around 8 inches (200 mm) high. It only fit under my Keurig machine by wedging it in tightly (though you can always brew in a smaller mug and pour into Ember).

At $150, Ember is aimed at those who really care about coffee temperature. For most coffee drinkers, cheaper accessories like mug warmers and non-heated travel mugs can get you close enough (especially considering how easy it could be to lose or bang up the expensive smart thermos). But if you fall into Ember's picky target audience – and want coffee flavor to stay optimized all the way to the end – you're getting a product that does its job well and without compromise.

You can buy Ember at select Starbucks stores or order online from the company website below (where it's currently back-ordered until February).

Product page: Ember

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