Stop making do with lukewarm brews. Here, three vessels that can retain your java’s heat no matter how long you let it linger.

IN A YEAR without commutes and trusty travel thermoses, not to mention office Keurig stations, we’ve struggled to keep hot brew at hand as we work from home. (And yes, your microwave is doomed to corrupt the flavor of even premium beans.) So we set off in search of insulating mugs to solve the problem more elegantly than a bulky plastic thermos, which seems uncivilized at home, and more effectively than thin, ceramic vessels that render a cup of java tepid before you’ve barely sipped half.

Armed with a kettle and a kitchen thermometer, we tested options ranging from high-quality classics like Le Creuset’s stoneware mug to app-enabled versions like the Ember Mug, which uses microprocessing technology to keep coffee or tea at a consistent temperature. We measured how long each option sustained coffee’s toastiness before the brew cooled to a temperature of 110 degrees, our definition of “lukewarm.”

Maintaining coffee’s heat guarantees more than a sense of comfort, according to Rod Johnson, co-founder of the Iowa-based coffee and tea company Blk & Bold. No matter what quality of beans you’re using, tepidness can ruin a cup, he said: “With hot coffee, you really get an opportunity to experience how it was meant to be enjoyed. Those flavor melds come through, and they’re so much more prominent than they would be in a flat, warm cup of coffee.” And don’t think that nuking your cupful in the microwave is a quick fix: “It impacts the drink’s chemical makeup and simply ruins how it tastes,” Mr. Johnson warned.

Here, our mug picks for caffeine fiends who pound their cup back relatively quickly, leisurely sippers who spend hours with a single cup and everyone in between.

Mug, $18, lecreuset.com

  1. For Speedy Sippers
    Le Creuset Mug
    Coffee gets lukewarm in: 30 min.

Those who tend to get their cupful down fast needn’t drink from anything fancier than a diner-style ceramic mug. But the gift-shop version you got on your last vacation can’t compete with an extra-dense stoneware model like Le Creuset’s standard coffee mug. Though the cup is light and sleek, the material provides the same heat retention you’d get with a thicker, clunkier mug, explained Nate Collier, the brand’s director of marketing communications and culinary. Our tests suggested that the mug’s tall and slim design does a better job retaining heat than models with a wider mouth. Pro tip: Run your mug under hot water before pouring in coffee, said Mr. Collier. That way, the stoneware won’t pull heat from the liquid to warm itself up.

Snow Peak Stainless Vacuum-Insulated Mug, $35, backcountrygear.com

  1. For Gradual Guzzlers
    Snow Peak Stainless Vacuum-Insulated Mug
    Coffee gets lukewarm in: 1 hour

Insulated mugs are the best bet for those who like to caffeinate with a bit more restraint. Drinking out of a metal cup might be reminiscent of a camping trip, but the heat retention is worth it: The stainless-steel material of Snow Peak’s mug, more polished than a bulky travel thermos, beat out the double-walled borosilicate glass we tested by nearly 15 degrees around the 60-minute mark. The exterior of the mug stays cool enough to let you cup it in both hands campsite-style, while traditionalists have the option of a collapsible handle. (And don’t worry, the stainless steel didn’t leave a metallic taste on our lips.) Bonus: a removable rubber cap, in case you want to bring your java along for a jaunt around the neighborhood.

Mug, from $100, ember.com

  1. For Day-long Drinkers
    Ember Mug
    Coffee gets lukewarm in: 2 hours—or never, if mug is kept on its charging port

If you’re the sort of wired morning person who only needs a sip of coffee now and then, consider investing in a smart mug like this sleek, foolproof model from California company Ember. Using a microprocessor-controlled heating system and companion smartphone app, the Ember Mug can keep a drink at any temperature you specify up to 145 degrees. (Just keep the coaster-like charging pad handy, as the battery lasts about 90 minutes.) Aside from a pulsating “on” light, the white and black models blend seamlessly with any breakfast setup without looking too tech-y. The only drawback: By continually applying heat, this innovation creates a dried-out residue at the bottom of the cup.

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