"How do I take my coffee? I like a nice cuppa left out to go cold," said no one ever. There's a considerable difference between an iced latte or cold brew and a once-piping-hot cup of now-tepid coffee. If you're team iced coffee, your biggest gripe will be ice melting and diluting your cup of joe, which is easily fixed by freezing coffee ice cubes (if you haven't already).
Hot coffee, on the other hand, is a little harder. Hand warmers and mug cozies don't work as well as ice cubes to alter the temperature of a drink, so there's not much you can do to keep your coffee hot short of relying on vacuum-sealed thermoses like Hydro Flasks and hoping for the best. But even the most expensive and reputable of thermoses can't keep your coffee warm forever — the Stanley thermos, often touted as the one that retains heat the longest, only promises hot coffee for up to 24 hours.
Enter the self-heating mug, an innovation that lets you reheat your coffee whenever you want. No need to leave your morning brew to the last minute so it stays hot until you reach the office; you can fill self-heating mugs with liquids of any temperature and tote them around for however long you need to before turning them on to heat up your drink.
