Roasting coffee at home once meant standing over a brazier with a thin, perforated metal or porcelain pan, as people did in the Ottoman Empire and Persia in the 15th century, stirring constantly so nothing scorched. Around 1650 Cairo produced the hand-cranked cylinder roaster, which spread through Europe and the American colonies. In 1722 English merchant Humphrey Broadbent urged everyone to roast their own green beans, partly to pick out moldy or insect-bitten berries and partly because dishonest sellers were dusting roasted coffee with lead powder to inflate its weight.

Home roasting stayed so common that Jabez Burns wrote in 1874 that portable roasters were as common in American homes as rat traps. The end came with the Arbuckle brothers’ one-pound paper bag of pre-roasted coffee in Philadelphia in 1864, clean electric commercial roasters patented in 1903 and 1906, and instant coffee after World War I. The revival grew from 1950s specialty coffee houses, the Siemens Sirocco and Michael Sivetz’s hot air roasters in the 1970s, and online green bean sales from 2001.

• A St. Louis coffee worker in the 1850s called selling pre-roasted coffee uphill work because everyone roasted in their own ovens.
• French farmers held out into the 1920s with outdoor glass and wire mesh drums, some powered by clockwork.
• Green beans can keep one to three years, and home roasters save 25 to 50 percent over retail roasted beans.
• Fluid bed roasters give a bright, light-bodied cup, while slower drum roasters produce heavier body and softer beans.
• Hobbyists aim paint-stripping heat guns into bread machines and mount rotisserie drums inside gas grills.