This is a book about credibility. Its characters are the many researchers who, across the eighteenth and nineteenth centuries, tried to address beer-brewing in ways they called ‘theoretical’, ‘philosophical’ or ‘scientific’. It is easy to imagine why such approaches were not always taken seriously. We are used to thinking of scientific investigators performing systematic experiments, searching for universal explanations in nature and communicating their findings on paper, usually by open publication. The craft and trade of beer-brewing conjures up an opposing set of ideas: down-to-earth artisans, mistrustful of theorists and tinkering; local customs of production, fiercely guarded from outsiders; skills passed down to a chosen few apprentices by hands-on experience. Nevertheless, a credible and coherent enterprise of brewing science existed by around 1880, the work both of theorists from outside the brewery, and of established brewers with theories of their own.

Credibility, for all investigators, meant showing that their claims were not merely valid, but actively useful to some relevant audience.