Martha Levie Talks Sourdough vs Yeast Breads

Martha Levie Talks Sourdough vs Yeast Breads

Watch this video as Martha Levi compares the differences between leavening in a loaf of store-bought bread, leavened by baker’s yeast, and a loaf of whole wheat sourdough that she made using her own sourdough start.

As she began her comparison, she said, “Today I have a loaf of store-bought bread, leavened by baker’s yeast.  This is a packet of your typical yeast you would find at the grocery store to make bread; Fleischmann’s active dry yeast. We used Fleishman all growing up, great baker’s yeast. 

“And then I have a loaf of whole wheat sourdough that I made with this jar of sourdough that I love. The start is just flour and water mixed together. I want to talk about the difference between these two leavening agents, what they do, what they do for your bread, and then what they do in your body when you consume them.”


She explained that a sourdough starter is made by mixing just flour and water. Then natural bacteria and wild yeast from the air in our homes, on the grain, and even on your hands, work on this mixture to begin a natural fermentation. “As you feed it more flour and water every day, you eventually build up this little condo for active bacteria that consume the starches,” in the wheat and improve the flavor of the bread.

That is what sourdough is, fermented flour and water that active bacteria have consumed for food. In turn, these good bacteria produce lactic acid and acetic acid.that the yeast enjoys. Working in tandem wild yeast and bacteria, produce carbon dioxide bubbles that leaven and flavor sourdough bread.

Sourdough leavening vs Bakers Yeast Bread
Photo by Lauren Nichols at Students Discover

In the process, the sourdough helps to break down natural irritants found in wheat, like gluten and phytic acid, making the bread more digestible and nutritious. In fact, many people who are gluten-intolerant can take pleasure in eating bread again.

Because sourdough bread is lower on the glycemic index, it can be good for diabetics too. Both lactic acid and acidic acid slow down digestion, so the natural sugar in bread is absorbed more slowly. This actually slows down all digestion, not just the bread, which breaks everything up in your digestive track so you can get all the nutrients out of it.

So there’s a lot of great things for your body with this as is the leavening agent for sourdough bread. Now, let’s compare that to baker’s yeast.


Sourdough was discovered about the time of the Egyptians; we’ve had it for thousands of years. Baker’s yeast was actually developed in the late eighteen-hundreds. Both use natural bacteria. Sourdough bacteria are called lactobacilli.

Baker’s yeast bacteria is saccharomyces. This is a different kind of yeast and was actually made in a lab. It has no wild yeast or bacteria that actually produce any liquid acid like sourdough does. But this yeast and bacteria work really, really fast.

The yeast consumes the sugars and spits out carbon dioxide at a massive rate because there are not bacteria producing acids that break down the glutens like in sourdough. So it just pops out in bubbles and raises it in about 30 minutes.

You can double dough in 30 minutes, but it’s not doing anything to help you digest the wheat. Commercial breads just rise super fast, so what you’re left with is this yeast in your body along with the irritants in the flour that are just sitting in your gut.

This is what it’s doing: yeast will get you to process starches super fast. It will spike your blood sugar. That’s why diabetics, number one thing, they can’t eat—well besides sugar—you think about a diabetic and you think, “Oh, they can’t eat sugar ” and they can’t eat bread because it spikes their blood sugar; it is because of this yeast.

The yeast, in and of itself, also can sit in your gut and grow, and grow, and grow, and grow. People will tell you, “Oh, these bacteria die at 140 degrees. You don’t have to worry about it.” But they don’t tell you is that when yeast is in distress, it sends out these little spores. It’s a coping mechanism so that it can survive, right? So it sends out these spores right before it dies and the spores turn into more yeast.

So this bread is filled with baby spores that you’re consuming, that get in your gut and grow. And you’ve got this yeast in there that sends all these messages to your brain that they want sugar, more and more, and more sugar. Pretty soon you’ve got all of this irritant, this very, very acidic, bad kind of acid. The yeast in there also causes candida, eczema, all sorts of problems in your body.

So not only are you consuming wheat that has not been broken down, you’re consuming this yeast that causes lots of issues in the body. So it’s just a better idea to go with the homemade sourdough bread versus the store-bought baker’s yeast bread for not only for taste but also for what it will do to the inside of your body.

She concludes her video with this, “it is just a better idea to go with the homemade sourdough bread versus the store-bought baker’s yeast bread for not only for taste but also for what it will do to the inside of your body.”

Have a happy day.

Martha Levie

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What are your sources? I want to learn more about this topic.

Madeline Weeks

What a great explanatory article! Thanks.


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