Long before refrigeration and vacuum packaging, humans relied on (0) FERMENTATION (FERMENT) as the principal means of food 1PRESERVE. From sauerkraut to kimchi, from sourdough to kefir, cultures around the world developed startlingly similar 2MICROBE techniques in complete ignorance of the biology involved. In recent years, these practices have enjoyed a conspicuous 3REVIVE among home cooks and artisan producers alike. Foods that were 4TRADITION considered peasant fare are now celebrated on the menus of fashionable restaurants, and a substantial body of research suggests that fermented products may indeed be 5HEAL, contributing to gut flora in ways that ordinary 6NUTRIENT science is only beginning to map. Experts nevertheless urge consumers to evaluate the more extravagant health claims 7CAUTION, since much of the popular coverage slides from genuine science into the merely 8FAD. What is not in doubt is that a kitchen tradition once dismissed as old-fashioned has returned to the centre of contemporary food culture.