How Long Have People Been Drinking Coffee?

People have been drinking coffee for hundred of years now. Obviously not in the same form, it was roasted, ground roughly, and boiled up over a fire for a while turning a vile bitter black. However when people discovered its stimulant qualities, it could make them work longer and study longer, it became a social norm. The health risks were only discovered as recently as fifty years ago.
Yet today ,coffee is more available and more attractively presented, with coffee chains popping up all over the globe.
Stimulants like coca leaves have been chewed in South America to give alertness and stop hunger, for centuries.
A relative of this stimulant is the coffee we drink now, which raises blood pressure and can cause heart disease and stress if used in excess.