"Dr. Pat McGovern, a biomolecular archeologist at the University of Pennsylvania Museum of Archaeology and Anthropology, in Philadelphia, is standing before some large and inscrutable scientific equipment on the museum’s fifth floor as he explains his process to me. 'We always start with infrared spectrometry,' he says. 'That gives us an idea of what organic materials are preserved.' From there, it’s on to tandem liquid chromatography–mass spectrometry, sometimes coupled with ion cyclotron resonance, and solid-phase micro-extraction gas chromatography–mass spectrometry. The end result? A beer recipe."