Teaming with Microbes to Create a Sourdough Starter

Field Trips for All of Us: Transformative Adventures for Children and Their Adults

Introduction

Teamwork makes the dream work! A simple, beautiful truism taught to me by our younger child, Ellyett. I say this phrase often when kids work together. It reminds us of the most consequential science idea I know; Ecosystems are all about teamwork! For most of our time on Earth, humanity lived in relatively small groups that were also all about teamwork through community care. In this activity, you and your family will participate in the multi-day process of cultivating wild yeast and lactobacillus bacteria to produce a working sourdough starter. Not only is this a great way to prepare tasty bread, it’s also a great example of obtaining a yield by nurturing nature in your own home, together!

Activity

To engage in this activity, you’ll need dechlorinated water and about a cup of flour; dechlorinated water because chlorine will kill the very microorganisms we’re trying to cultivate, and organic whole wheat flour because it contains the greatest variety of nutrients our microbes will feed on and because it is not treated with chemicals that may have killed off any wild yeast or bacteria in the flour. You will also need a glass jar or plastic container with about a four-cup capacity. A kitchen scale that measures grams would be helpful but is not required.

1. Mix 20 grams (or 2 level teaspoons) of dechlorinated lukewarm water and 20 grams (or 2 rounded teaspoons) of flour together in your loosely covered container and mark the level on the container or a piece of tape on the container. Putting a rubber band around the container and the original fill level works great for this.

2. Store in a warm dark place for 1-3 days. I put mine on top of our refrigerator. The inside of your oven is a good place as long as you remember to take it out when using the oven!

3. Check your starter regularly and when it has tiny bubbles on its surface (filled with carbon dioxide: a product of yeast fermentation) and a nice nutty smell add 40g of water (4 level teaspoons) and 40 grams of flour (4 rounded teaspoons) and again, mark its level on the side of the container.

4. Wait one day checking your starter regularly. It may rise and fall and that’s okay! At this point add 80g of water (8 level teaspoons) and 80 grams of flour (8 rounded teaspoons).

5. At this point, your starter should have risen a lot, be full of air bubbles, and have a good sour (not rotten). You’ve done it! Now your starter needs a name. I call mine Gen, short for Genesis. The next steps involve stabilizing your starter and getting into the routine of keeping your ecosystem in a jar alive and well.

Here’s a link to a video of my favorite baker talking more about the background behind sourdough starters, demonstrating the process, and talking about what to do with your starter once you’ve got it going. A Frenchman's Guide to Making Sourdough Starter. If you’re interested in baking and history, we highly recommend Townsends playlist on breadmaking!

Nature Science

My obsession with teaming with microbes began when I read a book with that phrase as its title, Teaming with Microbes: The Organic Gardener's Guide to the Soil Food Web, and came to realize how critical soil microbes are for sustaining life on Earth. Microbes, those invisible creatures we need a microscope to see, get a bad rap in general and are even more unpopular after the COVID-19 pandemic. Indeed, I have little positive to say about viruses! But their equally maligned microbial buddies, including bacteria and yeast, include many species that benefit humans in many ways. Soil bacteria break down organic matter and release nutrients in a form that plants can uptake. Beneficial gut bacteria (our microbiome) do much the same for the organic matter we eat. There are those essential bacteria and yeasts responsible for fermenting yogurt, pickles, sauerkraut, kombucha, bread, beer, and wine.

Regarding fermentation, starters sustain a complex community of many different microbes, including many bacteria and yeasts, a single-celled type of fungi. The most central microbe we are teaming with is a particular species of yeast used by both brewers and bakers. The common names of this yeast are baker's yeast and brewer’s yeast (Saccharomyces cerevisiae). Fermentation is a process that starts with glucose (a simple sugar) and yields energy and two products: carbon dioxide and ethanol.

Glucose  ⇨  Ethanol + Carbon Dioxide + Energy

Or in chemical notation:

C6H12O6  ⇨  2C2H5OH + 2CO2 + E

Bakers are interested in the bubbles formed by the release of carbon dioxide during fermentation; the alcohol evaporates before or during baking. Brewers are most interested in the alcohol. However, brewers of Champagne and other forms of bubbly alcohol do their brewing under pressure so the carbon dioxide carbonates their beverages. Other brewers just let the carbon dioxide bubble off during the brewing process. Lactobacillus bacteria are also involved in making sourdough. Lactobacilli produce lactic acid (CH3CH(OH)COOH) as a byproduct of their metabolism of glucose. Lactic acid lowers the pH of sourdough giving sourdough its characteristic sour taste and a longer shelf life by creating an inhospitable environment for other bacteria during the breeding-making process.

More important than this specific example of nurturing microbes to make bread is the idea that rather than beating the rest of the natural world into submission we humans can team with other organisms to obtain a yield. All land-based people have an ethic of caring for the life on which they depend. Caring for your sourdough starter will support you to do the same.

Educational Ideas

Factory-like schools sort students into grade-level age-matched classes based on their date of production based on the assumption that children with the same birthdate can be treated as equivalent. They are expected to master skills one at a time in an orderly sequential fashion. The best way to enforce this kind of learning is to have students practice isolated skills (e.g., memorizing names) on simple, similar, fragmented, and decontextualized tasks (matching the names of different organisms to their descriptions). 

Contrast this teaching method with how we learn our way around a forest or neighborhood or how we learn to walk, talk, and become people who take care of children. Those of us developing an ecological approach to how we nurture learning environments, see knowledge as a richly interwoven, non-hierarchical, dynamic web of interdependencies. We see knowledge as constructed by us through relationships with our physical and social environments. We encounter knowledge as we encounter the forest through playing, observing, interacting, climbing, etc., and making sense of our experiences through reflecting individually and through conversation with others. 

Rather than expecting students to practice isolated skills on simple, similar, fragmented, and decontextualized tasks, we support children in making sense of their experiences in the world as they process it. As part of this process, we encounter the same phenomena, ideas, and skills repeatedly coming upon them in different contexts and from different points of view each time, learning our way around a little bit more. Making increasing sense of the world through repeated experiences bends linear mastery into a spiral. Viewed from the top it appears that we return to the same topic cyclically but viewed from the side we see that our understanding is richer after each encounter.

When we support children's learning by making sense of their experiences, we no longer have the burden of selecting micro-tasks that match their age or ability. Complex real-world tasks, like making a sourdough starter, provide entry points for people of different ages with diverse abilities and experiences. This activity provides many opportunities for younger children to use their senses to observe and use their words to describe what they observe. It also provides a good context for doing a lot of measuring and counting. For older children, this activity provides opportunities to learn about big ideas like the notion that no thing comes from nothing and no thing disappears; matter just changes form. I’ve used this to support upper elementary through middle school-aged kids to help them learn about the chemical summary formulas for yeast fermentation using ball and stick chemical modeling kits and the benefits of lactic acid in delaying the spoiling of food. This activity also supports children coming to understand at a gut level (pun intended), the importance of microbes for personal and planetary well-being. For me, the biggest understanding that this activity supports people adding to is the understanding that we can obtain a yield by nurturing ecosystems.

The fact that we can use the same rich experiences with kids of different ages has two practical implications for how we guide children. First, it means that kids can spiral through the same activities multiple times and learn new things each time. Second, we can use the same experience in multi-age groups understanding that the kids will each be learning different skills and ideas at different levels through their shared experience. Sometimes I have different conversations with different kids about the same experience and sometimes I talk with a diverse group knowing that some kids understand what we’re talking about and others are just bumping into an idea for the first time. From my point of view, there is no harm in kids hearing about things they can’t quite grasp.

Wrap Up

Nurturing a sourdough-starter community is a fun way to learn all kinds of things. And, obtaining a yield by teaming with other people and other lifeforms may be the single most important basic skill a person can learn. For some different ways of teaming with life to obtain a yield, check out Relational Gardening and Composting and Deep Mulching