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Smart cups: hot stuff or just for mugs?

Smart cups: hot stuff or just for mugs?

Francesca Hornak tries out this year’s must-have gift for smartphone-addicted coffee snobs

Francesca Hornak tries out this year’s must-have gift for smartphone-addicted coffee snobs

Francesca Hornak | December 18th 2018

My husband calls me “asbestos mouth”. While he has to leave every hot drink until it’s tepid, I can’t drink a cup of tea without topping it up from the kettle. I order coffee “extra hot”, and then put a woolly hat over my cup. But as hard as I try, my efforts to keep every sip as hot as the first have so far proved futile, especially after having children – toddlers being hardwired to interrupt parents trying to take a tea break.

A lukewarm verdict? Ember’s iOS app

Could a “smart cup” – a hi-tech mug that promises to keep your drink at exactly the right temperature – be the miracle product I’m looking for? Or is it the latest example of Silicon Valley loopiness, over-engineering products to within an inch of their life and convincing us we need something we don’t?

Ember is dubbed the Apple Watch of mugs (this may or may not excite you) and syncs to an app on your smartphone. Sold in Apple Stores and online, its price ranges from £79.95/$79.99 (for the basic ceramic mug) to £159.95/$149.99 (for a travel model). As well as keeping your drink at exactly your preferred temperature, the Ember app also tells you when to take out your teabag – the brewing times vary according to whether you’re drinking green or black tea – and suggests an optimum temperature for a cappuccino versus other coffees. If you’re an iPhone user, you can sync your Ember to the Apple Health app and track your caffeine consumption, and even receive alerts when you’ve reached your chosen upper limit. (Non-iPhone users can track their caffeine intake by jotting down in a notebook how many cups of coffee they’re drinking. Or by using their memory.)

Glowstone, a small, crowd-funded venture from British engineer Thomas Gosteloe, offers a less corporate, lo-tech choice. While the Ember resembles an old iPod reincarnated in mug-form, the Glowstone (which costs £129/$164.95) looks like a normal bone-china mug with a Wedgewood-blue honeycomb pattern. Like the Ember, it’s too big to fit under a Nespresso machine. Unlike the Ember, it’s dishwasher-safe. You’re meant to charge the Glowstone on a coaster, pour your tea or coffee, and a red light glows at the base when it’s ready to drink. It promises to keep it at the “optimum drinking temperature of 60-65°C” for an hour.

Ground control The Glowstone

I don’t agree that 60-65°C (140-149°F) is optimum, preferring my tea at least five degrees hotter. With the Ember, too, the upper limit is 65°C. Why so low? Perhaps, after the notorious case in America when a woman won a huge pay-out from McDonald’s after a coffee scalded her, they can’t chance it any higher. Anyway, by the time Ember’s app pings to tell me that my drink has reached “Francesca’s preferred temperature”, I’ve already drunk half of it.

How would the cups fare in a temperature test? Ember uses the principles of convection, via cooling and heating elements in the cup’s sides, to keep the liquid inside at a uniform temperature. Glowstone’s mug has an inbuilt heating element and temperature-detection technology at the bottom. Armed with a meat thermometer, I conducted a very scientific experiment. I lined up the cups, alongside an ordinary bone-china mug and – just for fun – a £1 reusable, insulated cup from Starbucks. I poured the same volume of tea into each one and waited until it cooled to 65°C. After half an hour, the tea in non-smart china mug had dropped to 29°C (84°F). The tea in the Starbucks cup was 37°C (99°F). The tea in the Glowstone mug was 49°C (120°F)* and the tea in the Ember was 63 degrees (145°F). If that’s hot enough for you, this could be an expensive revelation.

Neither the Ember nor the Glowstone that I tried would be practical for use on the go. They’re too heavy, they don’t have lids (apart from the more expensive Ember Travel Mug) and they need daily charging. So here’s a thought. If you hate your drink cooling down, why not invest in a traditional double-walled, stainless-steel Thermos Flask? It may be associated with ramblers and birdwatchers, but it’s wireless, never needs charging and is a fraction of the price of a smart mug. In fact, it’s so terminally uncool it’s probably due a millennial revival. (126°F)

*Update: Glowstone suggested the mug the author tried may have been faulty and sent her another one to try. She performed the same experiment and got slightly better temperatures of 50°C (122°F) and 52°(126°F).