Aged coffee has some oomph in its body without much acidity. It may or may not have some funk or "bagginess" (a burlap taste from storage). And it may be mellow and smoky, or (if it's aged in a barrel) oaky, woodsy, winey or many other "-y"s. But each aged coffee is different, and that's part of what makes them interesting to coffee drinkers these days!