German scientists have developed a coffee mug that gets your joe to the right temperature and keeps it there, Der Spiegel reports. The secret is phase-change material, waxy stuff used in home-building to maintain temperatures indoors. It's also stuffed inside winter jackets, and if these scientists have their way, it will soon be stuffed into the structure of porcelain mugs and sold at a store near you.
When the coffee hits the cup, it melts the PCM, which absorbs the heat and keeps giving it off at a steady clip. The scientists found a PCM that melts at 136 degrees Fahrenheit, which they say is the perfect drinking temp for coffee. The material also could eventually be used to keep perishable food from spoiling or to keep machine parts from overheating.