In most cases, a packet of yeast weighs 7 grams.
That’s equivalent to ¼ oz. Or approximately 2 ¼ teaspoons by volume.
You might already know that yeast is a rising agent in baking. It’s the ingredient responsible for leavening dough and creating the crumb for whatever you’re making. But there’s more to it.
Not all yeasts are the same..so which one do you choose?
In this article, I’ll walk you through the different types of yeast in the way that I learned them during culinary school. As a beginner baker, there’s a lot to keep straight. We’ll stick to a few simple rules that are most important. We’ll cover,
- The different kinds of yeast and when to use them.
- How much you’ll need for common cooking scenarios.
- How to substitute when you don’t have the same yeast a recipe calls for.
By the end, you’ll be baking like a pro.
In This Article
What Is Yeast?
Let’s start with a little bit of science. We won’t get too deep, so bare with me.
Yeast is a living organism. It’s in the air all around us.
Even though yeast is only a single cell, it needs many of the same accommodations that you or I might. That includes food, warmth, and moisture.
Yeast’s scientific name (Saccharomyces cerevisiae) literally means “sugar-eating fungus.” For most people, this is 80% of what you need to know about it!
When yeast devours sugar and starch, it transforms them into carbon dioxide and alcohol. This process is called fermentation, and it’s a baker’s best friend.
How Yeast Makes Dough Rise
Yeast feeds on the sugars in your flour, which creates carbon dioxide.
The CO2 gas then gets trapped inside the stretchy, elastic dough. In a warm environment, the gas expands, causing the dough to inflate. This is rise!
Rise is what makes your cinnamon rolls fluffy. Brioche bread, soft. And pizza crust extra chewy.
Yeast also creates alcohol during fermentation, which is why it’s used for brewing beer, wine, kombucha, and soy sauce. What few people realize is that alcohol adds excellent flavor to your baked goods.
Yeast vs. Other Leavening Agents
Yeast isn’t the only “leavening” agent that you’ll find in most kitchens.
You can also create a rise, usually very quickly, by mixing baking soda or baking powder with an acidic ingredient. This is due to a chemical reaction between the basic powder and acid.
Unlike yeast, powder leaveners won’t contribute a meaningful flavor to baked goods.
On the other hand, it can be quick and easy to use a powder. Yeast is naturally occurring, so you can collect it yourself or buy packets, but it works more slowly because it needs time to grow.
Types of Yeast
According to science, all culinary yeast is the same species of organism. Why then do we have so many different types in the grocery store?
The short answer is that, over time, some strains have become more adept at specific jobs.
There is baker’s yeast and brewer’s yeast, depending on the application you need the leavener for. Brewer’s yeast produces both carbon dioxide and alcohol in equal amounts.
For this article, I’ll focus on baker’s yeast.
Bakers yeast strains have evolved to produce a significant amount of carbon dioxide and only a bit of alcohol.
Under the umbrella of baker’s yeast, there are different types of yeast, like dry, powder-like yeast, or fresh, crumbly yeast. Each distinction has more varieties, like active dry, instant, or cake yeast.
Not all baker’s yeast comes in a packet. There’s fresh yeast that hasn’t been dehydrated and can be purchased as a refrigerated, soft, compacted brick. But your options don’t end there.
Making your own supply of yeast is as simple as leaving out an open container of flour and water. Yeast from the air will populate the container, and you can store it indefinitely.
You’ve probably heard of sourdough starters. It’s not as intimidating as it sounds. At its most core, a starter is just a culture of yeast that you keep alive by providing it with fresh flour and water.
Admittedly, there is a particular convenience to using commercially available packet yeast. This is especially true if you don’t bake from-scratch goods every day.
Here are the most common types of yeast you’ll find, what they’re best suited for, and how they differ.
Active Dry Yeast
Active Dry Yeast is dormant until proofed. The granules are larger than instant dry yeast, so it isn’t as quick to rise. It must be dissolved in water with a tiny bit of sugar to activate.
This is the most versatile and best option for artisan or no-knead doughs. You can also use it for baked goods that will proof in the refrigerator for an extended period.
You’ll find it sold in packets or jars in the baking aisle at the grocery store. Store it in your fridge or freezer to keep the yeast fresh with a longer shelf life.
Instant Dry Yeast
Instant Yeast, otherwise known as Rapid or Quick-Rising Yeast, can be added directly to the dough and doesn’t need to be fed or activated beforehand.
The dry granules are smaller and finer than the ones in an Active Dry packet. There are enzymes and additives in Instant Yeast to help the reaction along and cut down the time it takes for the dough to rise. Often, if a recipe calls for two rise times, you can skip one when using this kind of yeast.
You can use this variation of dry yeast for all doughs. It works exceptionally well for quick breads and doughs with a light, airy, crumb texture.
When shopping for Instant Yeast, you’ll find it in packets or jars in the grocery store baking aisle. Store this yeast in your fridge or freezer for optimal freshness and shelf life.
Fresh yeast, sometimes called cake yeast, wet yeast, or compressed yeast, isn’t as common in your grocery store as the dried stuff. It’s highly perishable and will be kept in the refrigerated section.
These small square cakes of fresh yeast cells are most often used by professional bakers. If you’d like to use this kind, you’re better off going to Whole Foods, a restaurant supply store, or asking your local bakery if you can buy some from them.
This variety is sold by weight and is most often found in 2oz blocks which are about the same size as four sticks of butter.
Fresh yeast has a soft, crumbly texture and is best for recipes that require long, slow fermentation. In addition, it stays active for longer than dry yeast, so it’s best for recipes that require multiple proofs.
How Many Packets Do You Need?
On average, one packet of yeast, either Instant or Active Dry, can leaven one pound of flour (4 cups or ~455g). For fresh yeast, use .6oz or 17g for a pound of flour.
Active Dry Yeast and Instant Yeast are interchangeable at a 1:1 ratio. That means if your recipe calls for one or the other, you can swap it for the other kind without changing the measurement.
Keep in mind; if you’re using Active Dry Yeast instead of Instant, you will need to add about 10-15 extra minutes of rise time to get similar results. Also, if you use Instant instead of Active Dry, you can skip dissolving the yeast in liquid. Instead, you’ll add the Instant yeast directly into the dough.
You’ll need to use 3x the amount called for when trying to substitute fresh yeast for instant yeast. And when swapping fresh yeast for active dry yeast, you’ll use 2 ½ x the amount called for.