You’re at home, and you decide to do some baking. You find a good recipe, you gather the ingredients, and suddenly you realize you have instant yeast instead of active dry. Can you use them interchangeably?
Thankfully, the answer is yes—just as long as you do it the right way. Before we dive into numbers and proportions, it’s good to gain a bit of insight into this seemingly magical ingredient that makes your dough rise and turn into soft and fluffy baked goods.
The Most Common Types of Yeast and How They Work
There are three main types of commercial yeast that you can find in most stores. Although they all serve the same purpose, they each have specific characteristics.
- Active Dry Yeast (ADY): This is the traditional kind that’s used in most cake, bread, and rolls recipes. With only up to six percent of moisture, it’s a very dry yeast variety and sold in its dormant form, meaning it needs to be activated before use. This entails mixing it with lukewarm liquid and a pinch of sugar, then leaving it for a few minutes to bubble up or “proof”. (If nothing happens by the 10-minute mark, it’s likely to have gone bad.) About 25 percent of its yeast cells are dead, and they’re used to encapsulate the live granules that will eventually make your baked goods rise. Although it’s rather sensitive to thermal shock when baking, it’s very stable and has a long shelf-life: it can last for up to six months if stored in a dark, cool, and dry place; and for up to a decade when frozen.
- Instant Yeast (IY): Also known as rapid-rise yeast, this is the preferred option for impatient bakers who would rather get down to business right away. Because all the cells are alive and active, instant yeast doesn’t need to be activated with liquid, so it can be mixed directly with the dry ingredients. The granules are super fine and extremely dry with only three percent of moisture, which makes this type of yeast the most concentrated and driest of all commercial options. Just like ADY, it can last for up to six months when stored in a dark, cool, and dry place (such as in a jar stored on the bottom shelf of the fridge); and even longer when frozen.
- Fresh Yeast (FY): This option is less popular and usually more difficult to find. As the name suggests, FY belongs in the fridge and is highly perishable (it can only last up to three weeks), which is why many prefer the dry options. Nevertheless, it’s a favorite amongst experienced bakers because it’s said to provide a richer flavor and a better rising quality compared to other yeasts. It’s sold as a dense and beige block that contains living and viable yeast cells exclusively. While it doesn’t need to be “activated” per se, it still needs to be dissolved into some lukewarm liquid with a pinch of sugar prior to use.
How to Substitute a Kind of Yeast for Another
Swapping different kinds of yeast for each other is very easy, and it doesn’t really affect the flavor. All you need to do is know their composition and how they work. To recap:
- ADY contains 75% living cells.
- IY contains 100% living cells.
- FY contains 100% living cells.
To substitute one for another, you just need to keep in mind those numbers and perform the right calculations. Don’t worry, it’s easier than you think.
- If you’re using ADY instead of IY: Increase the amount by 25% to make up for the dead yeast cells contained in ADY. Activate it with a bit of the wet ingredients and a pinch of sugar, and expect the dough to take 10-15 minutes longer to rise. (For example, if you need 1 tsp of IY, use 1 1/4 tsp of ADY.)
- If you’re using IY instead of ADY: Lower the amount by 25% to make up for the difference in viable yeast cells. Mix it directly with the dry ingredients, and expect the dought to rise faster by 10-15 minutes (For example, if you need 1 tsp of ADY, use 3/4 tsp of IY.)
- If you’re using FY instead of IY: Given the standard 0.6-ounce block size of FY, you’ll need three times the amount of IY to make up for the difference in moisture. Crumble and dissolve it in some of the wet ingredients and a pinch of sugar, then let it sit for a few minutes before adding it to the mix (For example, if you need 1 tsp of IY, use 1/2 block of FY.)
- If you’re using FY instead of ADY: Use double the amount to make up for the difference in moisture. Crumble and dissolve it in some of the wet ingredients and a pinch of sugar, then let it sit for a few minutes before adding it to the mix. (For example, if you need 1 tsp of ADY, use 1/3 of a block of FY.)
Though these are the general rules of yeast conversions, you’ll find that seasoned bakers often do it all by eye, as they’re more familiar with the different kinds of leavening agents and their dynamics with other ingredients in varying recipes. Practice makes perfect, after all, so experiment as you bake, and you’ll soon have a natural knack for which (and how much) yeast to use with your favorite recipes.