Starbucks Is Now Selling $150 Mugs That Keep Coffee at a Constant Temperature The Ember mug already has backing from a handful of celebrities. BY KEVIN J. RYAN, FREELANCE WRITER @ WHERESKR Nov 21 ...

In addition to keeping coffee at a constant temperature, his employees have discovered the mug keeps ice at zero for 12 hours. “It also works for hot chocolate mix with boiling water,” Ma said.