Fermentation is behind a lot of the food you eat

What did you have for breakfast today?

Whether it was buttered toast, yogurt and granola, or even just a cup of coffee... David Zilber says that odds are, at least part of it was fermented.

He should know. After all, as a chef and former director of the Fermentation Lab at Noma, that's his specialty.

So what is fermentation, anyway? Zilber defines it as "the transformation of one food into another with the help of microbes."

"Grape juice? Wine. Cucumbers? Pickles. Milk? Yogurt. Flour? Bread. All of that, all of those transformations, use microbes."

Those microbes are everywhere. They're outside, floating through the air. They're inside, on your kitchen counter or the bananas in your fruit basket. They're even in your mouth, and on your skin. And a large number of them produce lactic acid, which is key to the process of fermentation.

Those lactic-acid-producing microbes use enzymes to process the simple sugars found in carbs and starches, and turn them into energy. The byproduct of that process is lactic acid (plus, in some cases, ethanol and carbon dioxide). Add it all together, and you get complex, unique flavors that come only from fermentation.

"In the Venn diagram of foods that microbes like, and foods that humans like, there's a lot of overlap there," Zilber says. "When they get to party down in our food supply, we seem to like what they do."

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This episode was produced by Hannah Chinn, edited by Rebecca Ramirez and fact checked by Tyler Jones. Maggie Luthar was the audio engineer.