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How does fermentation work?

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Quick answer

Fermentation works when microbes like yeast or bacteria break down sugars without oxygen, producing things like alcohol, acids, and gases. It's how dough rises, milk becomes yogurt, and grapes become wine. Microbes consume sugars in the absence of oxygen. Yeast produces alcohol and CO₂; bacteria produce acids.

Step by step

  1. Microbes consume sugars in the absence of oxygen.
  2. Yeast produces alcohol and CO₂; bacteria produce acids.
  3. The CO₂ makes bread rise; acids preserve and flavor foods.
  4. It's an ancient way to preserve food and create new flavors.

People also ask

What is fermentation in simple terms?
Microbes breaking down sugars without oxygen to make alcohol, acids, or gas.
How does yeast make bread rise?
It ferments sugars in the dough, releasing carbon dioxide bubbles that puff it up.
Why does fermentation preserve food?
The acids and alcohol it produces create conditions that stop harmful microbes from growing.

Part of the guide: Food & Kitchen Science →