What Does Yeast Do in Bread?

If you plan to make a loaf of bread, you’ll notice one recurring ingredient: yeast. Most people know that yeast is an imperative ingredient for bread baking (unless, of course, you’re making a yeast-less loaf). But what exactly does this magical ingredient do?

In bread, yeast acts as the leavening agent. In other words, it helps bread rise and retain its shape. However, yeast also lends a helping hand with overall flavor and scent. If your recipe calls for yeast, make sure you use it (or find a suitable substitution).

Hi! My name is Michelle, and I make bread fairly regularly (especially sourdough bread – yummy!). I almost always use yeast, which got me thinking – what exactly does yeast do in bread? I decided to do some research and share what I found.

Want to know what yeast does in bread? Keep reading to find out!

What is Yeast?

Yeast is typically sold in small packets. Upon opening the package, you’ll find tiny granules that almost look like tan sugar. 

What exactly are these little granules, though?

Yeast is a type of microorganism. More specifically, it’s a fungus. Don’t let that word make you run for the hills, though. This is a good type of fungus that’s highly nutritious (and delicious when baked inside of a loaf of bread!),

There are many different kinds of yeasts for bread-baking. The most common are active dry yeast and instant yeast. Although similar, they are not the same thing. Ensure you’re using the correct yeast for the bread you’re making – or it could end in disaster!

4 Things Yeast Does in Bread

Before heating your oven or turning on your bread machine, you’ll need to make your bread dough. Most bread will require water, yeast, salt, oil, and flour – although others may have additional ingredients.

Why is it crucial to add yeast if your recipe calls for it?

Here are the top four things that yeast does to bread (and why you shouldn’t attempt to make your loaf of bread without it):

1. Leavening/Rising

The most prominent thing yeast does in bread is allow it to “leaven,” which is just a fancy word for “rise.”

Basically, if you don’t use yeast in a loaf of bread that requires it, you’ll end up with a flat and yucky product you’ll have to chuck in the trash can.

How does yeast work in the dough, though?

Essentially, yeast is responsible for fermentation, which converts sugar to carbon dioxide gas and alcohol. After being produced, the gasses get trapped inside the bread dough, resulting in expansion. 

2. Improves Flavor

Now, I’m not going to sit here and say that yeast is bursting with flavor – it’s not a chocolate truffle!

However, it’s not to say that yeast isn’t a supporting character.

Yeast helps with overall flavor development. This basically means that yeast will help promote the flavors of your bread, ensuring that it turns out delicious – no matter how basic or extraordinary the ingredients are. 

If you leave yeast out, you’ll notice a difference the second you bite into a slice.

3. Enhances Aromas

Let’s be honest – there is nothing quite like the smell of a freshly baked loaf of bread.

Now, for some, that’s because they’ve made a delightfully sweet loaf of bread like this. For others, they’ve created a savory masterpiece like this cheddar twist bread.

But whether you’re making something bursting with flavor or keeping it simple, like white or wheat, one thing is for sure – yeast lends a helping hand in enhancing the overall aroma.

So, the next time you’re taking a big whiff of your freshly baked loaf of bread, say a quick “Thanks” to the all-powerful yeast.

4. Helps With Overall Shape and Structure

Lastly, yeast helps your loaf of bread retain its shape.

This is done through a process called “gluten development.” This network of gluten strands helps trap the carbon dioxide, ensuring it doesn’t escape during the baking process.

The result?

Bread that retains its glorious shape and structure. AKA, you won’t have to worry about your loaf of bread rising and then collapsing before you pull it out of the oven – which would be a complete disaster, wouldn’t you say?


Now you know precisely what yeast does in bread. Pretty cool, huh? Before you head out, I recommend checking out the frequently asked questions below. You’ll likely learn a few essential things about yeast in bread baking!

What happens if you don’t put yeast in bread?

If you do not put yeast in the bread, it will fall flat. That said, using yeast in bread recipes that call for it is essential. If you don’t want to use yeast, you’ll need to find a suitable substitute, such as baking powder, or find a yeast-free bread recipe to follow.

Does adding more yeast make bread fluffier?

Adding more yeast to your bread dough can make it fluffier, yes. However, you need to be careful. If you add too much yeast, the opposite effect will happen. Basically, your bread will produce too much gas and collapse before it’s even time to bake it!

How much yeast do I use for 4 cups of flour?

How much yeast you’ll use per four cups of flour depends mainly on the type of bread you’re creating. It’s always best to follow along with your recipe. However, if you don’t have instructions, you can typically be successful with two teaspoons per four cups of flour.

Yeast’s Vital Role: Elevating Bread

Basically, if you want your bread elevated in every way, you’ll want to use yeast. Yeast is necessary for creating the much-needed leavening, or “rise,” in your loaf. It also enhances overall flavor and scent while allowing bread to hold its shape. Superstar ingredient? You bet!

Do you use yeast in your loaves of bread? Or do you use another ingredient? Do you have a yeast-free bread loaf recipe to share with us? Let’s talk about it in the comment section!

About Michelle
I have been a lover of sweets since day one. This led me on a self-taught baking journey starting at the age of 13. It's been over 10 years since the start of my baking adventures, and I’ve learned a lot along the way. Now, people rave about my delectable treats, whether it’s a chocolate cake or a strawberry crepe.

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