How long will a coffee mug keep hot?

The length of time a coffee mug keeps a beverage hot depends on several factors, including:

- Material of the mug: Ceramic and stainless steel mugs generally insulate heat better than glass or plastic mugs. Double-walled mugs, which have a layer of air between the inner and outer walls, are particularly effective at keeping heat in.

- Lid: A lid helps to trap heat inside the mug and prevents heat from escaping through the top.

- Initial temperature of the beverage: The hotter the beverage is when poured into the mug, the longer it will stay hot.

- Ambient temperature: The temperature of the room or environment in which the mug is placed also affects how long the beverage stays hot. In a cooler environment, the beverage will cool down more slowly.

With all these factors considered, a well-insulated ceramic or stainless steel mug with a lid can typically keep a beverage hot for several hours. However, it's important to note that no mug can keep a beverage hot indefinitely, and the exact length of time will vary depending on the specific mug and conditions.