The 3:1 rule
Fresh yeast is roughly 70% water; dry yeast is about 8%. That water difference is why you need three times the weight in fresh yeast to get the same rising power: 7 g dry = 21 g fresh.
Handling fresh yeast
- Crumble into lukewarm liquid (below 38 °C) — hot water kills it
- It dissolves less readily than dry, so whisk before adding flour
- Keeps about two weeks refrigerated, or freeze in portions
- It has a distinct, slightly beery smell — that is normal
Why bakeries use fresh
Fresh yeast gives a slower, more controlled ferment and a slightly rounder flavour, which matters in long-fermented breads. For home baking the difference is small; convenience usually wins.
Converting a recipe
If a recipe calls for 21 g fresh and you only have instant, use 7 g — no other adjustment needed. Active dry would be about 9 g, since it is roughly 25% weaker than instant.
Frequently Asked Questions
Is the ratio always 3:1?
For fresh to dry by weight, yes. Instant and active dry differ from each other by about 25%.
Can I use fresh yeast in a bread machine?
Not recommended — machines assume dry yeast and the timing assumes its speed.
How do I store fresh yeast?
Wrap tightly, refrigerate up to two weeks, or freeze in 20 g portions.
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