Instant vs Active Dry vs Fresh Yeast

All three common baker's yeasts are the same species doing the same job: eating sugars in the dough and releasing carbon dioxide and flavor. What differs is how they are processed and packaged. That affects how much you need, whether you dissolve the yeast first, and how long it keeps.

This guide explains each form, gives a conversion table you can use with any recipe, and covers water temperature and storage. It is meant to let you bake from a recipe written for a different yeast without worrying about the switch.

Active dry yeast

Active dry yeast is dried into coarse granules, and the process leaves an outer layer of inactive cells around each one. The classic method is to dissolve it in warm liquid for 5 to 10 minutes, until creamy and foamy, before adding it to the flour. That step also confirms the yeast is alive.

Many current brands have finer granules and work when mixed in dry, but they still start a little slower than instant. If a recipe calls for active dry and gives a rise time, expect it to be accurate for that yeast; switching to instant may shorten rises by 10 to 20 percent.

Instant yeast

Instant yeast, also sold as quick-rise, rapid-rise or bread machine yeast depending on the brand, is milled finer and dried more gently. It hydrates quickly, so you can whisk it directly into the flour and add liquid at any comfortable temperature. It is forgiving, potent and keeps well, which makes it the most practical choice for most home baking.

Some rapid-rise products include extra enzymes and are designed for a single quick rise. They work in most recipes, but in long, slow fermentations the flavor benefit of time is partly lost, so plain instant yeast is the better all-rounder. Osmotolerant instant yeast is a specialty version for very sweet doughs such as brioche and panettone.

Fresh (cake or compressed) yeast

Fresh yeast is a moist, crumbly block of live cells with about 70 percent water. Many professional bakers like its reliable, gentle activity in enriched doughs. Crumble it into the liquid or directly into the flour; it dissolves easily.

It is perishable. Kept wrapped in the refrigerator it lasts roughly 2 weeks; it should smell pleasantly yeasty and be uniformly beige and crumbly. Gray, sticky, dry-edged or sour-smelling yeast has gone off. Freezing is possible, but it often weakens fresh yeast, so use more or treat frozen blocks as a backup.

Converting between yeast types

Use weight when you can; teaspoons of fresh yeast are not practical. These ratios are close enough for everyday baking. Adjust rise times by watching the dough rather than the clock.

• 7 g instant = about 9 g active dry = about 21 g fresh
• 1 teaspoon instant (about 3 g) = about 1¼ teaspoons active dry
• To convert fresh to instant, divide the fresh weight by 3
• To convert active dry to instant, multiply by 0.75
• When swapping in fresh yeast, reduce the recipe's liquid by a few grams if the dough feels slack

Water temperature and other yeast killers

Dried yeast dissolved in liquid does best at 38 to 43°C (100 to 110°F), roughly comfortably warm on your wrist. Instant yeast mixed with flour tolerates liquid up to about 49°C (120°F) because the flour cools it. Yeast starts dying around 55°C (130°F) and dies rapidly near 60°C (140°F).

Cold liquid does not kill yeast; it only slows it, which is the basis of overnight and cold-retarded doughs. Salt and large amounts of sugar both draw water away from yeast cells. Mixing salt straight onto concentrated yeast for a long time is best avoided, but in normal mixing, combining them in the flour is fine.

Storing dried yeast

Unopened packets and jars keep at room temperature until the printed date. After opening, seal the jar or fold the bag tightly and store it in the refrigerator for about 4 months or the freezer for about 6 months or longer. Use it straight from the cold; there is no need to warm it first. If you are unsure whether an old jar is alive, dissolve a teaspoon with a pinch of sugar in warm water and look for foam within 10 minutes.

Common questions

Can I use instant yeast in a recipe that says to proof active dry yeast?

Yes. Use about 25 percent less by weight and either add it to the flour or dissolve it in the same warm liquid. The dough may rise somewhat faster, so check it early.

Is bread machine yeast the same as instant yeast?

In most cases, yes. Brands label the same fine, quick-hydrating yeast differently. Check the package; if it says no proofing is needed, treat it as instant.

How much fresh yeast replaces a 7 g packet?

About 18 to 21 g of fresh yeast replaces one 7 g packet of instant yeast, and roughly 16 to 17 g replaces a packet of active dry.