Data for: Sourdough starters exhibit similar succession patterns but develop flour-specific climax communities

Five researchers grew a total of 40 starters from 10 different flour types: 4 replicates each of five flours containing gluten–unbleached all-purpose flour (processed from Triticum aestivum), red turkey wheat (Triticum aestivum), rye (Secale cereale), emmer (Triticum dicoccon), and einkorn (Triticum monococcum) – and five gluten-free flours – teff (Eragostis tef), millet (Eleusine coracana), sorghum (Sorghum spp.), buckwheat (Fagopyrum esculentum), and amaranth (Aramanthus caudatus). The all-purpose, red turkey wheat, emmer, einkorn, rye, and millet flours were milled at Boulted Bread Bakery (Raleigh, NC), while the teff, sorghum, buckwheat, and amaranth flours were purchased from commercial vendors online. On day 0, two level tablespoons of flour and two tablespoons of distilled water were mixed in a half-pint wide-mouth glass jar with a sterilized spoon. All spoons were washed with soap and water and wiped with 70% ethanol immediately before mixing. A paper towel was fastened over the mouth of the jar with a rubber band to prevent large particles or insects from settling into the jar while still allowing environmental microbes to colonize the flour-water mixture. After 24 hours, we measured the maximum height of the starter in cm, described the smell(s) of the starter using free association, then mixed the starter and measured pH using short-range (0–6, 0.5 interval) Hydrion Brilliant Paper (MicroEssential Laboratory, Brooklyn, NY). Next, we and transferred 1 mL starter to a sterile, labeled 2-mL microcentrifuge tube, which was stored at -20°C for DNA sequencing. Then we removed 1 tablespoon of sourdough to discard. Finally, we added 1 tablespoon fresh flour and 1 tablespoon water to the remaining starter and mixed thoroughly with the spoon. These measuring and refreshing steps were repeated once a day (at 24-hour intervals) for 14 days. We collected three 1-mL samples of each flour type (n=30) and three 1-mL samples of distilled water to represent the resource inputs to each starter on day zero. We also collected a daily 1-mL aliquot from each starter on days 1, 2, 3, 6, 10, and 14 (n=240), as part of the discard. All aliquots were transferred to a sterile, labeled 2-mL microcentrifuge tube, which was stored at -20C for DNA sequencing. Together with the flour and water aliquots, a total of 273 samples were shipped on dry ice for DNA extraction, PCR amplification, and Illumina multiplexed sequencing of the bacterial 16S v4 region using the 515f/806r for bacteria at the Fierer Microbial Community Sequencing Lab (Boulder, CO).