Sourdough for Science

A Science of Sourdough Project

*We are looking for participants!*

The microbial communities in sourdough are easy to grow and study, making them a great study system for home experiments and science education! By participating in a real science project, students and non-students alike can help us solve the mysteries of bread.

The Mystery: Humans have been baking bread for at least ten thousand years. While bakers understand how to make starters, the underlying biology of the species in these starters remains mysterious.  Sourdough for Science aims to reveal how these communities form over time and understand how factors such as flour type or geography, impact these communities.

What you’ll do: We will guide you through growing a “wild” sourdough starter using only water and flour following a standardized two week protocol. Each day you will measure the height and pH of your starter and record its smell (all of which are indicators of how the microbial communities are changing over time). You will submit these to us at the end of the experiment.

How your data will be used: Your data will be compared with other participants, all over the world, who have completed the same experiment. Together we can use these data to learn how different flours affect microbial growth over time – and how those microbes affect the taste and texture of bread.


Get the Instructions and Lesson Plan!

(If you aren’t a teacher or student, don’t worry, anyone can participate!)


Variations on the Basic Experiment

Indoor/Outdoor Experiment

*Seeking Participants!*

While some of the microbes that colonize a sourdough starter might come from the flour or the water or even your own hands, its possible that some of the microbes are drifting in from the surrounding environment. From our work on microbes in houses we know that the microbes that are inside your house or school are likely different from those outside.

The Power of Flour

*Seeking Participants!*

In the summer of 2017, Erin McKenney worked with 66 students from 46 counties at the NC Governors school to culture and compare the different bacteria and yeast living in different types of flours. The preliminary results suggest that whole grain flours may contribute different microbes (ie. more fungi) compared to all purpose flour. But how do differences in flour microbes impact the starter community? You can test this by following the Sourdough for Science protocol using different kinds of flour so that you can compare how the characteristics of the starter (pH, height, and smell) differ between flour types.

 Succession Experiment Summer 2019

*No longer accepting submissions*

In the summer of 2019 Erin McKenney collaborated with teachers in Raleigh to engage over 275 middle school students to grow their own starters and study the way microbial communities change over time. The students followed the Sourdough for Science protocol using ten different types of flour. We are using DNA sequencing techniques to discover which microbes colonized the nascent sourdough starters on successive day.