And coffee hot from dawn till dusk. It will also keep your coffee lip-blistering hot for way too long. Keeping things hot with a vacuum flask is a problem solv

And coffee hot from dawn till dusk. It will also keep your coffee lip-blistering hot for way too long. Keeping things hot with a vacuum flask is a problem solved 100 years ago. But that's the other side of these mugs: they are supposed to bring the temperature down to (and keep it at) the temperature you specify. Double-walled mugs don't do me any good if 30 minutes later the fluid is still at 198F/92C.