What's the Difference Between Instant and Active Dry Yeasts?

The single-celled microorganism, yeast, is what creates the magic that makes bread rise. It ignites the fermentation process that transforms a dense ball of dough into a soft loaf of bread. It does this by feeding on sugars in flour, and expelling carbon dioxide in the process.

But not all yeast is the same. There are around 1,500 species of yeast, but when it comes to using it to make food, the main star is brewer's yeast (Saccharomyces cerevisiae). And you only have to know the translation of the Latin name to figure out what it does: "sugar-eating fungi."

When it comes to baking, you have even more options. Dry yeast is the most common form of yeast used at home by bakers. It's available in two forms: active and instant. But what's the difference between the two?

What Is Instant Dry Yeast?

Instant yeast, also known as bread machine yeast or rapid rise yeast, has fine granules that dissolve easily and quickly so you can combine it directly with your dry ingredients. It's stable and consistent, and created so all the microorganisms are alive. That means you don't have to worry about killing the yeast cells or that any will already be dead. That's important because you can stock up on instant yeast and keep it in bulk for baking. (Fast-acting instant yeast is slightly different and works best with doughs that require just one rise and don't need to be refrigerated.)

Quick Tips:

Very stable; will store safely for months (or freeze for years)
Can withstand temperatures up to 130 degrees Fahrenheit (54 degrees Celsius)
Best for doughs that need more than one rise
Suitable for cold-proofed doughs

What Is Active Dry Yeast?

Active dry yeast is a dehydrated, ground yeast. It is the most popular form for home baking and the one you see most in grocery stores. It has bigger granules and also is extremely perishable. It needs to be rehydrated, or "activated" with warm water and a little sugar (depending on the brand). This is known as proofing or blooming, and is necessary to check if the yeast cells are still alive. You'll know the yeast is alive if it starts to foam and bubble within several minutes. If nothing occurs, this is a sign that the yeast is dead and should be discarded. Although active yeast has this extra step before using, it's versatile and works for almost any recipe.

Quick Tips:

Highly perishable and requires proofing before use
Can be killed in liquids at temperatures higher than 115 degrees Fahrenheit (46 degrees Celsius)
Best for doughs that need more than one rise
Suitable for cold-proofed doughs

fresh and dry yeast — Fresh baker's yeast, seen here next to granules of dry yeast, is a slurry of yeast and water formed into a crumbly, solid block. It's mainly used by professional bakers and must be refrigerated or frozen, as it is highly perishable.
Lumi Studio/Shutterstock

Substituting One for the Other

So now that you know the difference, what happens if your recipe calls for one type of yeast, but you have only the other on hand? Can you substitute? Yes, you can, but there are a few things to keep in mind.

If you have only instant yeast on hand but your recipe calls for active yeast, you want to skip the proofing step — combining the yeast in warm water to dissolve the granules — and mix the yeast directly with the dry ingredients. But first reduce the amount of yeast by 25 percent. You still need to add the water meant for activating the yeast to your liquid ingredients even though you won't be using it to proof to ensure consistency.

Substituting active yeast for instant yeast you'll want to do the opposite. First, you have to increase the amount of active yeast your recipe calls for by 25 percent. So if your recipe calls for 1 tablespoon of instant yeast, you'll need 1.25 tablespoons of active yeast. Plus, you'll need to proof the active yeast first to begin the fermentation process and ensure it's alive.

For the majority of recipes, you can use these yeasts interchangeably without any issues. Just be aware that rising times may vary from what the recipe states and the flavor may vary slightly too. And the longer the dough rises, there will be more nuances in flavor.