The Complete Guide to Yeast Types

Published Categorized as Food
Fresh yeast (cake yeast)Simona Stoyanova

I used to get intimidated by baking. In fact, I’d do everything I could to avoid it. One day, I grew tired of premade dough and its list of 1,001 ingredients. No matter what I did, my baking never came out the way I wanted it to taste and look like. And I knew precisely who the culprit was.

When I started to learn how to bake, I saw just how many misconceptions I had about this cooking method. One of them was that working with yeast and making bread rise was this complicated and challenging process that could go wrong in countless ways.

Of course, I understood just how wrong I was when I started learning how to bake and baked my first loaves of bread, pizzas, and desserts. It’s been years since—and now I’m thankful to Jim of the past that he took the first steps and finally learned how to do it.

In this post, I will share everything you need to know about the types of yeast with you.

Yeast can be incredibly intimidating to someone who’s just getting started with baking. 

Quite a few TV chefs and food bloggers are intentionally vague about yeast as they too haven’t done their research on the topic. 

Most authors and magazines skip through it because they don’t like to talk about the basics for one reason or another.

Yet most home cooks, like you and me, need exactly the basics to get started. So I thought to write this post and share everything I’ve learned to date with you.

What Is Baker’s Yeast?

Yeast is a type of fungus that’s naturally present and commonly found in nature. 

Yeast grows on plant leaves, flowers, fruits, and in soil. It’s also found on the skin and in the stomachs of birds and animals, including humans.

The type of yeast that’s used for baking is a specific strain in the yeast species. Baker’s yeast is a species called Saccharomyces Cerevisiae, which means “sugar-eating fungus” in Latin.

That’s also what makes yeast a different ingredient to cook with. It’s living! And you need to pay extra caution to the way you treat it because it’s susceptible to changes to its surrounding environment.

How Does Baker’s Yeast Work?

Think of yeast as a small organism, whose job is to eat sugar and convert it to gas (carbon dioxide and ethanol).

Here’s how this usually works.

You make a dough by mixing yeast, sugar, water, salt, and flour. I’ll write about the right proportions and techniques for this step some other time.

You knead the dough by hand or use a bread machine to stretch the flour’s gluten strands, making it springy and elastic.

Once the dough is kneaded, you let it rest. From this moment on, mother nature starts to do its magic.

Like the name Saccharomyces Cerevisiae suggests in Latin, yeast microorganisms feed on sugar. If you ask me, yeast seems to like sugar as much, if not more, than you and I do.

As the dough rests, the yeast microorganisms start to replicate until there’s no oxygen left in the dough.

At this stage, the yeast cells begin to feed on the flour’s sugars and, as a result, produce gas (carbon dioxide and ethanol). The gas is produced in tiny bubbles that slowly but surely make the dough rise.

Temperature, time, and the amount of sugars in the dough are three critical factors for the dough’s leavening. Warmer weather encourages yeast to feed faster. The more time it has, the more it can replicate. And the more sugar it feeds on, the more gas bubbles it will produce.

Hours in, the dough has risen and is ready for bake. Of course, depending on what you’re baking and what national cuisine the recipe comes from, it could take you multiple steps until the dough is prepared for baking.

The Three Types of Baker’s Yeast

Look for yeast in the baking aisle at your neighborhood grocery store, and the chances are that you’ll end up confused by the variety.

Buying baker’s yeast, however, doesn’t have to be complicated. It stops being so the moment you learn what you need—and where to look for it.

Marketing people who work at yeast producers try hard to convince you otherwise. Yet, at the end of the day, there are just three types of baker’s yeast.

The three types of yeast | fresh yeast, active dry yeast, and instant yeast

The three types of baker’s yeast are, in no particular order:

  1. Fresh yeast (cake yeast)
  2. Active dry yeast
  3. Instant yeast

Each of the three types comes from a slightly different yeast strain in the Saccharomyces Cerevisiae yeast species.

My favorite type of yeast is instant yeast. I’ll share the reasons why as I walk you through the similarities and differences between the three. 

For the time being, let’s focus on what that means for your baking (and how to pick the right one for your recipe).
For those of you who are scientifically curious, I’ll do a deep-dive into the species of yeast that bakers and brewers use later on—and tell you why they’re slightly different.

Fresh Yeast

The three types of yeast | fresh yeast
Fresh yeast

Fresh yeast is an active baker’s yeast with many names. It’s also called wet yeast, compressed yeast, and cake yeast.

Fresh yeast is sold in the refrigerated sections of grocery stores. If your local store carries it, you will usually find it near the milk cartons and butter packages. It’s usually sold in small cakes 0.6- and 2-ounces large. A 0.6-ounce cake yeast is enough to raise 4 cups of flour, and a 2-ounce cake will raise 9-12 cups.

Fresh yeast is wet and feels soft to the touch. It’s workable, but it also crumbles when you press on it. It consists of about 30% dry mass, with living yeast cells, and 70% moisture. In general, it is a highly perishable good and should be stored at temperatures below 45°F (7°C). 

Keep fresh yeast in the fridge in its original package and until the expiration date. As a rule of thumb, fresh yeast will last anywhere from several days to several weeks in your fridge.

If you opened a cake and you have leftover yeast, wrap it tightly or put it in an airtight container. Otherwise, it will dry out when exposed to air for prolonged periods.

It’s generally a good idea to proof cake yeast before using it. You can never be 100% sure that the yeast cells are active unless you proof the yeast.

Proofing yeast (or “proving yeast,” as it was called in the last century) is the process of making sure that the microorganisms inside it are alive and well before incorporating it with the flour.

To proof cake yeast, dissolve it with your hand with 1 teaspoon white sugar in lukewarm water and let it rest for 10 minutes.

Some authors will tell you that the water temperature should be between 100 and 110°F (38-40°C). That’s correct, but not useful if you don’t cook in controlled conditions like a test kitchen.

So here’s how you can “feel” if running water is lukewarm. Just run the water over your wrist. If it feels slightly warmer than your skin but not hot, it’s probably at the right temperature.

Substitute 1 serving of fresh yeast for roughly ½ servings of active dry yeast and ⅓ servings of instant yeast.

Fresh yeast should be substituted for smaller amounts of active dry yeast or instant yeast because it contains significantly more water than they do (on average, fresh yeast has 70% water compared to 5% for active dry yeast and instant yeast).

Active Dry Yeast

The three types of yeast | active dry yeast
Active dry yeast

Active dry yeast is made of small and dehydrated yeast granules. Active dry yeast consists of 92-95% dry matter and just 8-5% moisture.

Yeast producers make active dry yeast by processing fresh yeast using high heat. This kills the living cells on the surface of each granule and encapsulates the living cells inside it. The living cells remain inactive because of the lack of moisture.

When you mix active dry yeast with lukewarm water, you’re shedding off the dead cells on the surface and activating the living cells at the center of each granule.

“Lukewarm water” is usually tap water at any temperature between 100 and 110°F (38-40°C). If you don’t have a thermometer in your home kitchen, do this instead. When you run the water on your wrist, it should feel neither cold nor hold. That’s how you know the water is lukewarm.

To find active dry yeast in the grocery store, head to the baking aisle and search for it somewhere near the rest of the baking staples, like flour, scents, sprinkles, and toppers.

Substitute 1 serving of active dry yeast for roughly 3 servings of fresh yeast and ⅔ servings of instant yeast.

Instant Yeast

The three types of yeast | instant yeast
Instant yeast

Instant yeast is also known as instant dry yeast.

Instant yeast is reduced to 92-95% dry matter and 8-5% moisture. 

However, the process producers use to make instant yeast is significantly gentler than active dry yeast. Instant yeast contains only living cells and doesn’t need to be dissolved in water before use.

To use instant dry yeast, simply mix it with the flour and the rest of your dough’s ingredients. Proofing instant yeast is not recommended.

Another convenience of instant yeast is that you can mix it with salt and sugar crystals—and not worry about the yeast cells dying. Salt and sugar indeed can, in concentrations above 2-3% and a matter of several minutes, kill fresh and active dry yeast.

To find instant yeast in the grocery store, go to the baking aisle and look for it near the rest of the baking supplies like flour.

Substitute 1 serving of instant yeast for roughly 1.5 servings of active dry yeast and 3 servings of fresh yeast.

Compared to instant yeast, active dry yeast and fresh yeast have less leavening power because the former contains dead yeast cells and the latter contains significantly more water.

Fresh vs. Active Dry vs. Instant Yeast

The main difference between fresh yeast, active dry yeast, and instant yeast is their water content. Fresh yeast has 70% water, whereas both active dry yeast and instant yeast have just 5% water content. The lack of moisture keeps the yeast cells that they contain inactive, at least until they come into contact with water again.

Both active dry yeast and instant yeast are dry yeast varieties. The main difference between the two is that active dry yeast needs to be dissolved in water before use, and instant yeast can be mixed directly with the dough.

Remember this ratio for substituting yeast: 1 serving of fresh yeast is roughly equivalent to 0.5 (½) servings of active dry yeast and 0.3 (⅓) servings of instant yeast.

My favorite type of yeast is instant yeast. It’s easy to use and gets the job done without the hassle of fresh yeast or active dry yeast.

Here’s a table that puts these differences into perspective:

Fresh YeastDry YeastInstant Yeast
Contents30% dry,
70% moisture
92-5% dry, 
8-5% moisture
92-95% dry,
8-5% moisture
Yeast cellsLivingDead on the outside, living on the insideLiving
ProofingRecommended, but not required

(Proof for 10 minutes in water approx. 100°F or 38°C warm)
Recommended, but not required

(Proof for 10 minutes in water approx. 100°F or 38°C warm)
Not recommended

(Mix the yeast directly with the flour)
Substitution1 serving0.5 servings0.3 servings

Save this page in your browser’s bookmarks and come back to this table whenever you need a quick reminder.

Is Baker’s Yeast the Same as Brewer’s Yeast?

There are more than 1,500 species of yeast in existence.

In the food and beverage industry, yeast is generally used for baking (bread, pizza, desserts) and brewing (alcoholic drinks like beer and seltzer and non-alcoholic beverages like kefir and kombucha).

Baker’s yeast is slightly different from brewer’s yeast. Baker’s yeast is a strain of yeast that produces mostly carbon dioxide. Brewer’s yeast is a strain that produces carbon dioxide and sufficient quantities of alcohol.

Baker’s and brewer’s yeast are part of the same genus (Saccharomyces) and the same species (Saccharomyces Cerevisiae), but they represent different strains. 

Most breweries make alcoholic drinks like beer and seltzer, so brewers require yeast strains that produce carbon dioxide and ethanol. 

On the other hand, bakers want yeast strains that produce mostly carbon dioxide.

How to Proof Yeast

Remember, proofing is only for fresh yeast and active dry yeast.

Contrary to popular belief, you don’t need to proof yeast, fresh or dry. But proofing your yeast will help you avoid the mistake of making dough that never rises.

Also, you don’t need to and shouldn’t ever proof instant yeast. If you bought instant yeast, simply mix it with the flour and the rest of your dough’s ingredients.

  • Fill ½ glass, ⅔ soup bowl, or an empty jar with lukewarm water. The temperature of the water should be between 100 and 110°F (38-40°C);
  • At first, it’s best to test the water’s temperature using a thermometer. If you don’t happen to have a food thermometer at home, put your wrist under running water and make sure the water is warm, but not hot;
  • Add 1 teaspoon white sugar into your water and whisk it until it’s completely dissolved. Yeast feeds on sugar, so the added sugar in the water will get it started on feeding. When yeast feeds, it produces gas bubbles that contain carbon dioxide and ethanol;
  • Add the fresh yeast or active dry yeast to the water. Dip your hand in the glass, bowl, or jar and dissolve the yeast with it, stirring;
  • Let the mixture sit for 10 minutes.

After 10 minutes, you should see bubbles appearing on the surface. Based on how much yeast and water you put in, as well as the temperature of your water and the room, the amount of size of the bubbles will vary.

Don’t expect to see any volcanic eruptions or anything. But if you can see small bubbles continuously appearing on the surface from random spots inside your water… it’s alive!

This is a sign of yeast activity, which is exactly what you want to see. It shows the yeast you just proofed has passed the proofing test; it’s alive, well, and ready for your dough.

Bubbles are a signs that the yeast is active

If there’s no visible bubbling activity on the surface of your water, the yeast cells have most probably died. Discard the yeast since it won’t make your dough rise (and there isn’t a way to bring it back to life).

Does Yeast Need Sugar to Work?

Some recipes will tell you to proof yeast in water after dissolving 1-2 teaspoons of sugar in it. Is sugar really needed for activating yeast?

Putting the granules of active dry yeast in warm water helps them dissolve—allowing the living cells to separate from the dead cells and reactivate. Adding 1-2 tablespoons of sugar gets the yeast started on feeding.

Instant yeast can be mixed directly with the dough’s ingredients and does not need to be dissolved in water and proofed.

If the recipe asks for more than 1-2 tablespoons of sugar, it could be because you’re making a rich dough recipe.

In general, there are two types of dough: lean dough and rich dough.

Lean dough doesn’t contain extra sugar or fat. Once the yeast becomes active, it starts to feed on the dough’s starches, converting them to sugars. Lean doughs are crusty, chewy, and have a mild flavor. Examples include the doughs for making baguettes, French bread, Italian ciabatta, Irish rye bread, and most whole-grain bread varieties.

Rich dough (dough enriched with some kind of fat like butter) contains some sugar. Pieces of bread made with rich doughs have a softer crust and less chewy crumb and are more flavorful as a whole. Examples include the doughs for making brioche buns and Danish bread.

Rich dough contains added sugar and fat, but for reasons related to its taste and texture—not to the yeast’s feeding process.

Common Problems With Baker’s Yeast

Here are some of the most common problems that home cooks like you and me come across when they use yeast.

Why Doesn’t My Yeast Produce Bubbles?

Let’s look at a couple of problems that you can identify with the yeast’s proofing.

Since instant yeast shouldn’t be proofed, read this only if you’re having problems with fresh yeast or active dry yeast.

The yeast has expired. Check the expiry date on your yeast’s package. Yeast, fresh, active dry, and instant, can perish, especially if you try to use it long after the expiry date.

The water is too hot. Some recipes tell you to heat the water that you’ll use for proofing your active dry yeast. The problem with this advice is that you can easily overheat the water to a temperature above 110°F (44°C), killing the yeast cells.

Why Won’t My Dough Rise?

Even if you proofed your yeast, you might still have problems with your dough rising. Let’s take a closer look at a couple of them.

The room is too cold. Yeast thrives at temperatures between 75 and 90°F (24-32°C). If your dough sits for a long time in a room that’s colder than this narrow temperature range, the yeast microorganisms will die.

It’s too early; give it more time. It takes time for the dough to rise. Sometimes it takes less than what it says on the recipe; other times, more. There are several factors, like the temperature and humidity of the room, that can influence this. Stay patient and allow your dough the time to rise.

Yeast: My Best Picks

Here are a couple of my best picks for yeast at Amazon.

Instead of convincing you why they’re as good as I think, I’ll let you check them out and decide for yourselves.

The Bottom Line

This concludes my guide to the three types of yeast.

My favorite type of yeast, as I mentioned, is instant yeast. You get the same outcome as fresh yeast and active dry yeast but without any of the hassle.

What’s your favorite type of yeast? And why? Let me, and the rest of this post’s readers, know by leaving a comment below.

By Jim Stonos

When Jim isn't in the kitchen, he is usually spending time with family and friends, and working with the HCW editorial team to answer the questions he used to ask himself back when he was learning the ropes of cooking.