The Ember Tumbler is a cool, high-tech travel mug — but it can’t handle the heat

My coffee routine is needlessly fussy but fairly predictable. I wander bleary-eyed into the kitchen, add some water to the kettle, and start heating it to 200 degrees Fahrenheit, grind some coffee beans, get out the Chemex, add and rinse a new filter, put the whole thing on a scale, add 40 grams of beans, slowly pour in 600 milliliters of hot water, pour it into my trusty silver Yeti Rambler, and pad into the living room to either play with my son or look at TikTok on my phone. It’s a…