Four hundred years ago, Coffea arabica, a tropical shrub bearing glossy green leaves and bright-red berries, was virtually unknown outside of the Arab world and the corner of Ethiopia where it had been discovered in the ninth century—by a goatherd who, legend has it, noticed that his animals would get frisky and stay up all night after nibbling its berries. In the years since people figured out that coffee could affect us in similar ways, the plant has done a great deal for our species, and our species in turn has done a great deal for the plant. We have given it more than 27 million acres of new habitat all around the world, assigned 25 million farming families to its care and feeding, and bid up its price until it became one of the most valuable globally traded crops. Not bad for a shrub that is neither edible nor particularly beautiful or easy to grow.
Coffee owes its global ascendancy to a fortuitous evolutionary accident: The chemical compound that the plant makes to defend itself against insects happens to alter human consciousness in ways we find desirable, making us more energetic and industrious—and notably better workers. That chemical of course is caffeine, which is now the world’s most popular psychoactive drug, used daily by 80 percent of humanity. (It is the only such drug we routinely give to our children, in the form of soda.) Along with the tea plant, which produces the same compound in its leaves, coffee has helped create exactly the kind of world that coffee needs to thrive: a world driven by consumer capitalism, ringed by global trade, and dominated by a species that can now barely get out of bed without its help.