Scientists have created a “super” sourdough that could help breadmakers and microbiome researchers alike answer long-standing questions, including how a sourdough’s microbial makeup might make it more stable than others. The team created their synthetic sourdough by pulling bacteria and yeast from 8 spontaneously formed sourdoughs from around the world. These microbes fulfilled two criteria: 1) they occurred in 4 of the 8 spontaneous sourdoughs, and 2) they harbored at least 20 key genes associated with metabolic pathways critical to maintaining sourdough quality, including the fermentation and breakdown of different sugars. Seven species (5 bacteria, 2 yeasts) met these criteria, forming a global sourdough labeled “SDG.” Scientists compared SDG with a synthetic sourdough (SMC-SD43) modeled after one of the original 8 spontaneous sourdoughs. SDG contained 4 times as many fermentation-related genetic transcripts as SMC-SD43 and lost only 1 species over time as the sourdoughs were replenished, versus the 4 (50%) lost by SMC-SD43. SDG’s stability is attributed to the strong community structure of its resident microbes, where dominant, subdominant, and satellite members cooperate in different ways. Understanding which species play these different roles could help create sourdoughs and other fermented foods that retain their favorable qualities (like flavor) over time.