Skip to content
Know.itKnow.it
Create an animated lesson
On request

This article is free to read. Creating a lesson uses your daily or stored credits; review the language and settings before starting.

What is fermentation?

Food & CookingLesson on requestFree to read

Quick answer

Fermentation is a process where microbes like yeast and bacteria break down sugars into simpler substances such as alcohol, acids, or gases. It's how we get bread, yogurt, cheese, beer, and many pickles. Microorganisms convert sugars without needing oxygen. Yeast makes alcohol and CO₂ (bread rise, beer, wine); bacteria make acids (yogurt, sauerkraut).

Key things to understand

  1. Microorganisms convert sugars without needing oxygen.
  2. Yeast makes alcohol and CO₂ (bread rise, beer, wine); bacteria make acids (yogurt, sauerkraut).
  3. It preserves food and develops complex flavors.
  4. It's both an ancient food art and a modern industrial process.

People also ask

How does bread rise?
Yeast ferments sugars in the dough, releasing carbon dioxide gas that gets trapped and puffs it up.
Is fermentation the same as rotting?
No — fermentation is controlled microbial activity that preserves and flavors food; rotting is uncontrolled spoilage.
What foods are fermented?
Bread, yogurt, cheese, beer, wine, kimchi, sauerkraut, soy sauce, and many more.

Part of the guide: Food & Kitchen Science →