How long can brewed coffee sit out and stay fresh?Updated a month ago

Coffee will always taste the freshest immediately after brewing. However, what you put your coffee IN can also help you prolong the flavor and taste. For example, brewed coffee kept in an open container, like the drip pot, glass carafe or ceramic coffee cup, will probably stay fresh for 30-60 minutes—this is because the coffee is both hot and exposed to air, so it will oxidize faster, losing its freshness (also why day-old coffee tastes different). 

However, if you keep brewed coffee in a sealed container (like a thermos), this will allow your coffee to taste fresh for a few hours (unless the top is open). 

Coffee that is cooled (such as iced or instant-chilled) may stay fresher longer as well as the heat is immediately removed and so the oxidation reactions occur more slowly.