Yeast is the living organism that ferments dough, producing the carbon dioxide that makes bread rise. Three forms show up in baking, and the main difference between them is simply how you add them to the dough.
The three types
| Type | How to use | Notes |
|---|---|---|
| Active dry | Dissolve/proof in warm water first | Traditional; slightly slower |
| Instant (rapid-rise) | Mix straight into dry ingredients | Finer granules, no proofing |
| Fresh (cake) | Crumble into the dough | Perishable, short shelf life |
Converting and keeping it alive
Instant and active dry are close enough to swap in most recipes, with instant being a touch more potent — use about 25% less instant than active dry, or just swap 1:1 for everyday baking. Yeast is killed by heat, so keep proofing water lukewarm (around 100–110°F), never hot. Store dry yeast sealed in the fridge or freezer, and if a packet is old, proof it in warm sugar water first to confirm it still bubbles before committing it to a batch.
Frequently asked questions
Do I need to proof instant yeast? No — mix it directly into the dry ingredients.
Can I swap active dry and instant? Yes; instant is slightly stronger, so use a bit less.
What water temperature for yeast? Lukewarm, about 100–110°F; hotter kills it.