Yeast

A single-celled fungus that eats sugars in dough and gives off carbon dioxide and alcohol, which raise the bread and build flavor. Commercial yeast is one carefully selected strain, Saccharomyces cerevisiae, grown for fast, predictable rising and sold as fresh, active dry, instant, or osmotolerant yeast. Wild yeast lives in a sourdough starter alongside lactic acid bacteria and usually works more slowly. When a recipe says "yeasted," it usually means commercial yeast rather than sourdough.

By Henry Hunter · Updated October 1, 2026

Henry's notes from the bench

• Instant yeast is the easiest for most home bakers: it goes straight in with the flour. If you swap types, adjust the amount, because fresh, active dry, and instant aren't used gram for gram.
• Salt and yeast can sit in the same bowl, just don't leave them in a concentrated pile together for long. Mix them into the flour and you're fine.