Where other mugs keep their beverages warm till about noon, the Zojirushi keeps drinks warm all day long. In fact, it might even keep your drink too hot. Expert users know to let piping hot beverages cool off a bit before sealing it in the mug. America’s “best-selling travel mug” will keep your coffee an ambiguous level of hot for seven, five, or four hours, depending on where you read the description. Zojirushi’s will maintain heat at 154 degrees Fahrenheit for six full hours and 187 degrees for one hour.