How yeast makes bread rise
Intermediate Kitchen science
Yeast eats sugars in dough and gives off carbon dioxide gas and flavor, while gluten traps the gas so bread rises.
Written with AI help from the sources listed, and published by Cory. Spot a mistake? Tell us and we'll fix it.
How do you do it?
- Use water around 75-95°F for most doughs; above about 130°F you start killing yeast.
- Judge rising by size and feel (about doubled, slow spring-back when poked), not only the clock.
- For more flavor, let dough rise slowly in the fridge for 12-72 hours.
- Mix salt into the flour rather than piling it straight onto the yeast.
Why does it work?
Yeast is a living fungus. It breaks down sugars, many released from flour starch by its own enzymes, into carbon dioxide and alcohol, along with flavor compounds. Kneading lines up gluten into a stretchy net that holds the gas in bubbles, so the dough inflates. Yeast works fastest in warm dough, around 75-85°F, but a slower, cooler rise produces more flavor because it gives enzymes and bacteria time to work. Salt slows yeast and tightens gluten. In the oven, gas expands and yeast makes a last burst before dying at about 140°F, which is oven spring. Then starch and protein set the bubbles in place as crumb.
What are the common mistakes?
- Proofing in a too-hot spot — fast rise, flat flavor and a yeasty, boozy smell.
- Over-proofing — gluten stretches too thin, and the loaf collapses in the oven.
Still stuck? Watch someone do it on YouTube.
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