You know the feeling: you’ve measured out the ideal amount of coffee beans, ground them up just right, and labored over your Chemex until you’ve poured the perfect cup. You dump it into your to-go coffee mug and tighten the lid. An hour later, you take a sip, and . . . burn your mouth from the scalding brew that’s maintained its near-boiling temperature.
Hongbin “Bill” Ma, a professor within the Mechanical and Aerospace Engineering Department at Missouri University, always struggled to maintain a comfortable drinking temperature for his on-the-go coffee. Putting to use his understanding of thermal dynamics, Ma created the Lexo mug, a solution for those who need more control over their coffee temperatures.
The Lexo mug is made from stainless steel that uses vacuum insulation like most tumblers. Unlike others, however, it also houses a phase-changing material that reduces coffee to a drinkable 140 degrees Fahrenheit and maintains that temperature for up to eight hours. Here’s the science, from the Missourian:
‘Before you pour hot coffee into it, the material is solid, but after you pour the coffee, the material turns to liquid and absorbs the thermal energy,’ Ma said. ‘This energy is stored in the phase-changing material, and when the coffee temperature gets below the drinking temperature, the thermal energy is literally released back. In this way, we can keep the temperature almost constant.‘