Utilizing totally different flours for sourdough fosters totally different micro organism—and flavors

A brand new examine of the microbial ecosystem in sourdough finds that utilizing various kinds of flour fosters distinct bacterial communities, and that these variations contribute to the variation of sourdough aromas and flavors.

“Individuals bake sourdough everywhere in the world, and our previous research make clear the large variation within the forms of microbes present in sourdough starters, and the way these microbes affect the aroma of sourdough and the way rapidly it rises,” says Erin McKenney, corresponding creator of the examine and an assistant professor of utilized ecology at North Carolina State College.

“Our new work focuses on the position that various kinds of flour play in shaping these microbial ecosystems. Because it seems, the flour bakers use to ‘feed’ their starters performs a major position in figuring out which forms of bacteria thrive. And that, in flip, strongly influences the aroma that these sourdoughs produce.”

“In different phrases, our findings present that bakers can affect the aroma of their sourdough through the use of totally different flours, as a result of these flours will foster totally different communities of micro organism.”

For the examine, researchers developed a protocol designed to breed what bakers really do of their kitchens. The researchers created 4 sourdough starters utilizing 10 totally different flours, for a complete of 40 starters. The researchers used 5 flours that included gluten: unbleached all-purpose flour, pink turkey wheat, emmer, rye and einkorn; and 5 gluten-free flours: teff, millet, sorghum, buckwheat and amaranth. The 40 starters have been saved in the identical rising atmosphere and have been fed as soon as a day for 14 days.

The researchers collected knowledge from every starter each day. This included measuring pH and top, in addition to recording the aromas produced by every starter. The researchers additionally took samples of the starters for DNA sequencing, as a way to decide the variety and abundance of micro organism in every pattern.

“We discovered that the starters began out being pretty related to one another, however that modified considerably over time,” McKenney says. “Over the course of the 14 days, we discovered that every sort of flour shaped more and more distinct microbial communities. Basically, it seems that various kinds of micro organism are in a position to take advantage of the dietary compounds present in various kinds of flour.”

And when you’ve gotten totally different bacterial communities thriving on totally different dietary inputs, you get all kinds of metabolic outputs. In different phrases, totally different micro organism produce totally different smells.

“For instance, the bacterial group in amaranth sourdough produces an aroma that smells nearly precisely like ham,” McKenney says. “I’ve by no means smelled a sourdough that had such a meaty aroma. Rye produces a fruity aroma, buckwheat has an earthy odor, and so forth. There is a large quantity of variation.”

There have been additionally a pair surprises.

“One shock was that rye flour fostered a a lot wider range of micro organism than some other sort of flour,” McKenney says. “We discovered greater than 30 forms of micro organism within the rye starters at maturity. The subsequent highest was buckwheat, which had 22 forms of micro organism. All the different flours had between three and 14.”

The researchers additionally discovered that seven of the ten flours produced starters that included excessive ranges of micro organism which produce acetic acid. Solely starters made utilizing teff, amaranth and buckwheat have been missing the acetic acid micro organism.

“These acetic acid-producing micro organism made up between 12.6% and 45.8% of the micro organism within the starters from these seven flours,” McKenney says. “So it is enjoying a major position in these microbial ecosystems. That is shocking as a result of we did not even know one of these micro organism was present in sourdough till 2020. Our earlier work discovered that it was not unusual, however to see it at such excessive ranges, throughout so many forms of flour, was positively fascinating.”

And whereas all of that is scientifically compelling, it additionally presents some sensible insights for sourdough bakers.

“This examine presents insights into how bakers can modify the flour they’re utilizing of their starters to get the aromas and flavors they’re on the lookout for,” McKenney says. “We additionally discovered that the starters took 10 days to grow to be ‘functionally mature,’ or prepared for baking. And that is helpful for bakers to know, too.”

The paper, “Sourdough Starters Exhibit Similar Succession Patterns But Develop Flour-Specific Climax Communities,” is printed in journal PeerJ.

Extra data:
Erin A. McKenney et al, Sourdough starters exhibit related succession patterns however develop flour-specific climax communities, PeerJ (2023). DOI: 10.7717/peerj.16163

Journal data:
PeerJ

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