The Global Sourdough Project

Rob Dunn Lab | A Science of Sourdough Project


The Global Sourdough Project started out as an online survey, distributed to the general public, with the hope that it would find it’s way to sourdough bakers who keep their own starters. Over 1000 people, all over the world, filled out the survey – sharing where their sourdough came from, how it is maintained, and sharing stories of their unique flavors and unique origin stories. Five hundred and sixty of those bakers then sent us a sample of their sourdough starter. We are using genetic techniques (metagenomics, in the lingo of our tribe) to determine which species are present in the starter. Once we know which species are living in each starter, we will use statistical approaches to compare the different communities. By doing this comparison we can begin to understand the factors that influence which community lives in one starter relative to another, why your starter is different from that of someone else. Some bakers suggest (swear by, really) that the biggest factor influencing which species of microbes are found in a starter are the microbes that are on the bodies of the people who started it. Some say it is the grain that is used. Others, the climate. Others still, the water. Everyone might be right; it could be that each starter is influenced by many factors. But we don’t actually know. Now that we know the identity of the organisms in each of a hundreds of starters from around the world we are testing the relative influence of each factor using statistical models — the same sort we would use to understand why there are, say, more bird species in the tropics.

Bread and the microbes on which bread depends are at the heart of our agricultural civilization, the ancient marriage between humans and grains. They are also at the heart of the ways in which we come together to break bread and savor the rich flavors of wild microbes and tamed grains. By this same token, we hope that by studying starters together, we might all understand and savor more than any of us could on our own.

The Global Sourdough Project is just one of our various efforts to study sourdough starters.


Landis, E.A., A.M. Oliverio, McKenney, E.A., Nichols, L.M., Kfoury, N., Biango-Daniels, M., Shell, L.K., Madden, A.A., Shapiro, L.R., Sakunala, S.K., Drake, K., Robbat, A., Booker, M., Dunn, R.R., Fierer, N., Wolfe, B.E. 2021. The diversity and function of sourdough starter microbiomes. eLife  (Open Access)

Publication Companion Figures

Sourdough Starter Results Map

Project Update Dec. 2018

What Can You Do Now?

We are no longer accepting sourdough starters as part of the Global Sourdough Project, but we are processing and analyzing them in the lab.  For those of you who have chosen to participate in our project, know that we are taking care of your starter with love, even as we give it the occasional exploratory poke or prod. We will continue to post updates on this page as we go.

Regardless of whether or not you have sent us a sample of your sourdough, if you would like to stay updated about our results or events related to the project you can sign up for email updates as well. We won’t send you spam – promise.

We ARE looking for folks who are willing to take part in our Sourdough for Science and Wild Sourdough experiments, so regardless of whether or not your starter was a part of the Global Sourdough Project, there are still ways to help us study sourdough.

Additional Resources and Links

Sourdough Projects

Wild Sourdough

Sourdough for Science

Global Sourdough Project

The Belgian Experiment

More sourdough

Interactive map

Microbial species

Sourdough sonification

String of Yeasts


Lecture series

Sourdough photos

Media toolkit

Sourdough lesson plan

Making a starter

A guide

Wild Sourdough


Get to know your sourdough yeast

Liz Landis photos

IncrEDIBLE Science Resources

Global Sourdough Project Facebook Group

Behind the Science

It is hard to capture the work that goes on behind the scenes, but sometimes we remember to try to get snapshots of what some of our days look like.

The Sourdough Team

In its broadest scope this projects involves professors who study the evolution of food microorganisms (Ben Wolfe, Tufts University), the ecology of microbes (Tad Fukami, Stanford/Natural History Museum of Denmark), human evolution (Peter C. Kjærgaard, Natural History Museum of Denmark), the ecology of life in homes (Rob Dunn, Natural History Museum of Denmark/NC State University), the history of food (Matthew Booker, NC State University), and the culinary arts (Michael Bom Frøst, University of Copenhagen and Taste for Life).

But the truth is that the real leadership of this effort is being done by the people you see in this picture, younger people, people in whom we would be wise to trust the future of food ecology: Anne Madden, Angela Oliveira, Liz Landis, Erin McKenneyLauren Nichols, Lori Shapiro, and Lea Shell.  Together this team (which recently convened the 2019 Sourdough Summit, pictured on the left) are the ones leading this project. Each of them has a kind of superpower, but collectively they have a combined set of skills for the work at hand like no other team on Earth, from public engagement to art, from culturing to sequencing. Everyone involved in this project, including all of the public participants, does their part, but this group, leads. Everyone else knows well enough to, most of the time, just get out of the way.