Paulo Mazzafera punched a pea-sized disc out of a waxy green coffee leaf, then placed the disc in a small vial with a mixture of chloroform and methanol to dissolve it. Later, he loaded the extract, along with 95 other samples, into a high-performance liquid chromatography machine, which separates out each chemical component. When the plant physiologist returned to his lab at the University of Campinas in Brazil the next morning, he sat down at his laptop to examine the results. Scrolling from one chromatogram to the next, he scrutinized the peak representing caffeine. In one plant, it was missing.
Mazzafera ran the sample twice more and then, just before noon, called his collaborator Bernadete Silvarolla, based at the agricultural station nearby, to share the news. “Are you sure?” she asked. He was. In fact, he was thrilled. After screening thousands of plants over the course of two decades, his project to find a naturally caffeine-free coffee finally seemed to be bearing fruit. That was in late 2003.