Yeast Converter
Convert between active dry yeast, instant yeast, fresh yeast, and sourdough starter with accurate ratios. Get proofing instructions and rise time estimates for each yeast type. See also our Baker's Percentage Calculator and Cooking Converter.
How to Convert Between Yeast Types
Converting between yeast types is essential when a recipe calls for one type of yeast but you only have another on hand. The key is understanding that different yeast forms have different concentrations of active yeast cells. Instant yeast is more concentrated than active dry yeast because it has a finer granule size and more live cells per gram. Fresh yeast contains more moisture, so you need more of it by weight to get the same leavening power.
- Identify the yeast type your recipe calls for
- Identify the yeast type you have available
- Apply the conversion ratio (see table below)
- Adjust your proofing method based on the yeast type you are using
Conversion Ratios (by weight):
Active Dry Yeast = 1× (baseline)
Instant Yeast = 0.75× Active Dry
Fresh Yeast = 3× Active Dry
Sourdough Starter = 5.67× Active Dry
Example: 7g Active Dry → 5.25g Instant Yeast
Understanding Different Yeast Types
All commercial baking yeasts are strains of Saccharomyces cerevisiae, but they are processed differently to create distinct products with different handling requirements. Understanding these differences helps you substitute confidently and adjust your baking process accordingly.
Active Dry Yeast is the most common type found in grocery stores. The yeast cells are dried at high temperatures, which kills the outer cells and creates a protective shell around the living inner cells. This is why it must be dissolved in warm water (proofed) before use — the warm water rehydrates and activates the dormant cells. It has a shelf life of about 2 years unopened.
Instant Yeast (also called rapid-rise or bread machine yeast) is dried at lower temperatures, preserving more live cells per gram. Its finer granule size means it dissolves on contact with dough moisture, eliminating the need for proofing. It works about 25% faster than active dry yeast and can be mixed directly into flour.
Fresh Yeast (cake yeast or compressed yeast) is undried yeast with about 70% moisture content. It has the mildest flavor and is preferred by professional bakers for its reliable performance and subtle taste. It must be refrigerated and used within 2-3 weeks. It crumbles easily and dissolves quickly in liquid.
Sourdough Starter is a living culture of wild yeast and lactobacillus bacteria maintained by regular feeding with flour and water. It provides both leavening and the characteristic sour flavor. Because the yeast concentration in a starter is much lower than commercial yeast, you need significantly more starter by weight to achieve the same rise.
Yeast Conversion Reference Table
| Active Dry | Instant | Fresh | Sourdough Starter |
|---|---|---|---|
| 1 g | 0.8 g | 3 g | 6 g |
| 2 g | 1.5 g | 6 g | 11 g |
| 3 g | 2.3 g | 9 g | 17 g |
| 5 g | 3.8 g | 15 g | 28 g |
| 7 g | 5.3 g | 21 g | 40 g |
| 10 g | 7.5 g | 30 g | 57 g |
| 14 g | 10.5 g | 42 g | 79 g |
| 21 g | 15.8 g | 63 g | 119 g |
Example: Converting a Bread Recipe
A French bread recipe calls for 7 grams of active dry yeast. You only have instant yeast. Conversion: 7g × 0.75 = 5.25g instant yeast. Since instant yeast does not need proofing, skip the step where the recipe says to dissolve yeast in warm water. Instead, mix the instant yeast directly into your flour. The dough will rise slightly faster (about 25% less time), so check it earlier than the recipe suggests. Your first rise might take 45-60 minutes instead of 60-90 minutes.
Proofing and Activation Tips
- Water temperature matters: Too hot (above 120°F/49°C) kills yeast; too cold (below 95°F/35°C) slows activation
- Sugar helps proofing: A pinch of sugar feeds the yeast and speeds up the foaming test
- Test before using: If active dry yeast does not foam within 10 minutes, it may be dead — discard and use fresh
- Storage: Keep opened yeast in the freezer for maximum shelf life (up to 1 year)
- Salt kills yeast: Never let salt come in direct contact with yeast — add salt to flour first
- Altitude adjustment: At high altitude, reduce yeast by 25% to prevent over-rising
When to Use Each Yeast Type
Active dry yeast is best for traditional recipes with long, slow rises that develop complex flavors. Instant yeast is ideal for bread machines, quick breads, and when you want faster results. Fresh yeast is preferred for enriched doughs (brioche, challah, panettone) where its mild flavor shines. Sourdough starter is essential for artisan sourdough bread and adds unique flavor complexity that commercial yeast cannot replicate.
Frequently Asked Questions
Can I substitute instant yeast for active dry yeast?
Yes. Use 75% of the amount of active dry yeast called for. So if a recipe needs 7g active dry, use 5.25g instant yeast. You can also skip the proofing step — just mix instant yeast directly into your dry ingredients. The rise time will be slightly shorter, so watch your dough rather than strictly following time guidelines.
How much fresh yeast equals one packet of active dry yeast?
One standard packet of active dry yeast is 7 grams (2¼ teaspoons). The equivalent in fresh yeast is 21 grams (about ¾ ounce or a piece roughly the size of a large marble). Fresh yeast has 3× the weight of active dry because it contains about 70% moisture.
How do I convert a recipe to use sourdough starter instead of commercial yeast?
Multiply the active dry yeast amount by 5.67 to get the starter weight. For 7g active dry yeast, use about 40g of active, bubbly starter. Reduce the flour and water in your recipe by the amounts present in the starter (starter is roughly 50% flour and 50% water by weight). Expect significantly longer rise times — 4 to 12 hours depending on starter strength and room temperature.
Does the type of yeast affect bread flavor?
Yes, but subtly for commercial yeasts. Fresh yeast produces the mildest, most neutral flavor. Active dry and instant yeast produce nearly identical flavors. Sourdough starter produces distinctly different bread with tangy, complex flavors from the lactic and acetic acids produced by the bacteria in the culture. Longer fermentation times with any yeast develop more flavor.
How do I know if my yeast is still alive?
Proof it: dissolve the yeast in warm water (105-110°F) with a pinch of sugar. If it foams and bubbles within 5-10 minutes, it is alive and active. If nothing happens after 15 minutes, the yeast is dead and should be discarded. Instant yeast can be tested the same way even though it normally does not require proofing.
Can I use more yeast to make bread rise faster?
Technically yes, but it is not recommended. Excess yeast produces a strong, unpleasant "yeasty" flavor and can cause the dough to over-rise and collapse. The better approach for faster bread is to use instant yeast (which works 25% faster), increase dough temperature slightly, or add a small amount of sugar to feed the yeast. Patience produces better bread.