Once coffee is brewed it immediately starts to cool. A certain amount of cooling in the cup is obviously desirable so that the coffee drops to a temperature comfortable to the mouth but between the ending of brewing and drinking most of the heat needs to be held.
Most auto drip pots have a burner under the pot that can keep coffee warm but it is at the same time burning the coffee in the pot. This is about the worst possible way to keep coffee warm. It the burner is your only option, let your coffee get cold and warm it up in the microwave or even better make only as much as you will drink at a time without the burner.
For people who need to keep coffee warm for longer periods of time the best option is a vacuum bottle or a similar well insulated carafe. These hold the coffee at a warm temperature by not allowing the coffeeâ€™s warmth to escape.
There are a number of different designs and your personal needs will dictate much of your choice. If you plan to carry your coffee without you or are clumsy you may want to avoid a models that use glass. For people who notice metal flavors you may want to look for a model that has a glass inner lining instead of the more common metal lining.
Some vacuum units use a pump to push the coffee into the cup. This design is generally referred to as an air pot. This is the best option since it means that the lid is not constantly opened and closed as coffee is served. On the other hand if you need to take a few cups on the road this is probably not an option. Some units that are opened to pour have a push button that opens a valve that allows coffee to be poured without having to take the lid off. This is also a good choice.
UltimatelyÂ what should be looked for is a good tight seal and a good vacuum or other insulating material. Unfortunately itâ€™s tough to judge this just by looking so look at reviews.
One more thing that should be mentioned is that vacuum bottle can loose their vacuum. When this happens they will no longer keep beverages hot so if you notice a vacuum bottle that previously worked well is no longer keeping your beverages cold you have probably lost your seal and itâ€™s time to get a new vacuum bottle.
Regardless of how long your vacuum bottle or carafe can keep coffee warm the coffee will still deteriorate after brewing so keep your hold times as short as possible and brew more often. Obviously when you are traveling and want to take some coffee on the road this is not an option so a good vacuum bottle is the answer.