EVERY BITE OF CHEESE OWES ITS FEEL, FUNK, AND FLAVOR to microbes. The tangs and textures that define each type hinge largely on how those mini mobs break milk down into the smaller bits—amino, lactic, and fatty acids—that we taste and sniff. Cheesemakers add carefully selected microbes to the starting mix (usually milk, salt, and a digestive enzyme called rennet) or just wait for naturally present bacteria to do their thing; mongers also tweak moisture, salt content, and pH to manipulate the speed and extent of bacterial growth. Each choice influences how the final wheel turns out. Want a stinky, reddish rind? Wash the outside with oxygen-loving Brevibacterium linens to break proteins into amines (a derivative of ammonia, aka eau du cat pee) and sulfurs, creating a BO bouquet. Hoping for holes? Propionibacteria turn lactic acid into CO2 bubbles. The network here shows how combinations of these and other teensy critters create some of the world’s most beloved cheeses.