I’m on a baking spree lately. Not only am I not letting my oven take much of a break as I test out and write about baking recipes, but I’m trying to answer some of your top cooking questions. 

Especially the ones I wish others had answered when I was learning how to make homemade dough and bake bread, pizza, and desserts.

Today, I will try to demystify what I consider one of the most intimidating baking topics for beginner home cooks: the complicated relationship between salt and yeast.

Does salt kill yeast? Here’s the TL;DR answer:

Salt slows down yeast’s fermentation because it pulls moisture from yeast cells through a process called osmosis. In too high concentrations, salt can kill living yeast cells. For best results, add 2% salt to your dough.

When it comes to using salt and yeast for baking, I’ve made all the mistakes I can (and I’ll probably make some more, keeping you guys and gals posted). Then I’ve spent days researching them on blogs, cookbooks, and scientific journals on the Internet.

In doing so, I found a frustratingly low amount of information about using yeast, salt, and sugar for baking newbies out there and amateur cooks like me. 

Just as I like to do with this blog of mine, I’m setting out to fix this. So let’s get started.

Before we talk about the problems of marrying yeast and salt, let’s spend some time looking at their unique characteristics—and why we need to combine them when making yeast-leavened dough in the first place.

Why We Add Yeast to Dough

To put it simply, yeast makes your dough rise.

Yeast is a tiny organism, consisting of just one cell, that feeds on sugar. As it feeds on sugar, it spurts out small amounts of gas; a combination of carbon dioxide and ethanol.

Think of yeast as a microscopic biological machine that feeds on sugars for energy—and produces carbon dioxide and ethanol as a byproduct. It uses that energy to grow and multiply. This conversion is what bakers call fermentation.

When you add yeast to your dough and give it the time and conditions it needs to ferment, your dough rises as gas bubbles from the yeast’s fermentation get trapped in it.

There’s one thing you need to know about yeast. It isn’t much of a survivor. In fact, yeast is very perishable and highly susceptible to changes in its surrounding environment.

If you let freshly-mixed dough rest in a cold room, it won’t rise because the low temperature will kill the yeast. If you added too much salt to your dough, the salt crystals will pull too much moisture from the yeast cells, and the yeast cells will eventually die.

Yeast cells feed and reproduce best at temperatures between 80°F and 90°F (27-32°C). The optimal salt concentration in a dough, which won’t harm yeast cells, is about 1.8-2%.

There are also three types of yeast for baking: fresh yeast, active dry yeast, and instant yeast. I won’t go into the specifics for each one of them in this post. 

If you’re curious (and want to know what yeast to buy at the grocery store), check out my guide to yeast types for baking.

Why We Add Salt to Dough

Salt plays a more prominent role in baking than most home cooks think, King Arthur Bakery, an employee-owned baking company that dates back to 1790, explains on its website.

Salt adds flavor. This one time, I tried to make pizza dough without salt. My pizza came out intolerably bland. I’ve also made the mistake of adding too much salt to homemade bread. Let’s just say I couldn’t get enough water to quench my thirst that day.

When it comes to baking, how much salt in your flour is enough?

The right concentration of salt in flour is 1.8-2%. That’s about 0.02 pounds of salt per 1 pound of flour or, in more practical terms, 1 ½ teaspoon of salt for every 3 ½ cups flour.

Salt gives strength to your dough. Gluten gets a bad rap nowadays. No matter if you like gluten or not, you need to know that it’s indispensable for baking.

Gluten is a protein. Flour doesn’t contain much protein (most flours tend to have between 10 and 13% protein content). When you mix flour with water, the gluten it contains swells, forming a mesh of fine strands. This mesh makes up the structure of your dough, making it elastic and workable.

Salt gives your dough strength by tightening its gluten structure. This allows the dough to hold on to the gas bubbles that yeast produces better, helping it rise well and become airy. 

If your homemade dough is sticky and lacks volume, you might have forgotten to add salt (or didn’t add enough of it).

Salt slows down yeast’s fermentation. Salt is hygroscopic, which means it absorbs water. Yeast cells, on the other hand, are the most active in wet environments. 

When you add salt to your dough, the salt soaks up some of the water, which ends up dehydrating your yeast cells and slowing them down.

Dough tastes best when it’s gone through slow fermentation. For a number of reasons, slow fermentation is how your bread or pizza develops a rich aroma and complex flavor.

If you don’t add any salt to your dough, the yeast will ferment too quickly. Your dough will taste bland and underdeveloped. If you add too much salt, the salt crystals will soak up too much moisture and kill your yeast.

As long as you use salt in the right concentration (1.8-2%; see above), salt helps you slow down yeast’s fermentation—allowing the dough to develop a richer aroma and more complex flavor.

Why Don’t Yeast and Salt Get Along?

Yeast makes your bread rise, and salt gives the dough strength to hold on to the gas bubbles that yeast produces as it turns sugar into carbon dioxide and ethanol.

In their love triangle with flour, the marriage of yeast and salt produces airy and fluffy bread. So why do these two have such a complicated relationship?

It’s because salt and sugar can harm the cell walls of yeast cells.

Yeast is what biologists call a microorganism, a tiny living creature made of just one cell. For comparison, your body is estimated to have around 30 trillion cells.

The cell wall keeps a yeast cell together, protecting it from the outside world. If you damage or break the wall of a cell, it will have difficulty functioning or, in extreme cases, die.

When salt, sugar, or a combination of the two come into direct contact with fresh or active dry yeast, they pull plasma material from yeast cells’ walls. This reduces yeast’s ability to ferment dough or, in excessively high concentrations, kills yeast cells.

Every yeast cell has a semi-permeable cell wall. It can let moisture in and out, as long as it doesn’t get punctured or torn apart beyond repair. In the presence of salt, which pulls and soaks up water, yeast cells release some of their moisture, slowing down their growth and reproduction.

This chemical process, in which moisture gets drawn from Place A to Place B, is called osmosis. It’s the same process that butchers use to make salt-cured meat, like beef jerky or Italian prosciutto, and fishmongers use it for salted fish, like kippered herring and lox.

Home bakers like you and me usually bake bread or make pizza in small quantities. Since that usually means 1 pound of flour, 1 teaspoon sugar, and 1 to 1 ½ teaspoon salt, our margin of error is not that high. 

As this and this experiment prove, salt in this concentration isn’t enough to kill yeast, no matter if you’re mixing them dry or with water. 

Now that you know the science and the facts about mixing salt with yeast for home baking, I hope you feel less intimidated by it. 

At least for me, after I understood all of this, baking turned from a cooking method I would religiously avoid to one I wholeheartedly love to practice.

So much for yeast, salt, and sugar. It’s a love-hate relationship, folks. You can’t bake with them, and you can’t bake without them.

What should you be doing?

How to Mix Flour, Yeast, and Salt

I’m splitting my how-to guide in two from here on. The first part is for those of you who are using instant yeast, and the second is for the rest of you who might be using fresh or active dry yeast. 

In case you don’t know the difference between the two, check out my guide to baker’s yeast types.

If You’re Using Instant Yeast

If you’re using instant yeast, you can safely allow the yeast and salt to come into direct contact with each other.

Just put all of your dough’s ingredients together, add water, and start mixing it by hand or in a bread machine.

If You’re Using Fresh or Active Dry Yeast

If you’re using fresh yeast or active dry yeast, proof it before using it.

Yeast is perishable. Proofing is the process of making sure that the yeast cells are alive and well before mixing them with the rest of your dough’s ingredients and letting the dough rise. That way, you can avoid making the time-costly mistake of using dead yeast in the first place.

To proof yeast, fill a soup bowl with lukewarm water. Add 1 teaspoon of sugar, stirring it until it’s fully dissolved in the water. Finally, add the fresh yeast crumbles or active dry yeast granules and mix them gently with your hand.

Let it rest for 10 minutes. If, after that time, you see bubbles on the surface, you know that the yeast is alive and well. In case you don’t see any bubbles, the yeast has perished, and you should discard it; it simply won’t make your dough rise as the cells are not alive.

Home Cook World | How to proof fresh yeast (cake yeast)
How to proof yeast in four simple steps

Don’t add salt to the water you’re proofing your yeast in. It can slow down the yeast’s fermentation or, on rare but plausible occasions, kill the yeast cells in too high a concentration. 

Instead, mix the salt with the flour. As soon as the yeast has proofed, start mixing it with the flour and salt (i.e., make the dough just as you would normally do).

One thing I’d like to highlight is that you don’t need to dissolve active dry yeast. As this test showed, you can put it directly in your flour mix and bake with it—as you would do with instant yeast.

Nevertheless, I think that proofing is a good idea when you’re using fresh yeast or active dry yeast. Unlike instant yeast, the two types of yeast are much more perishable. A cake yeast or a pack of active dry yeast can trick you that it looks just fine, then never really make your dough rise. Proofing is, in that sense, a just-in-case and time-saving practice. Not a must-do.

Conclusion

Salt helps you control yeast’s fermentation. But add too much of it, or do it at the wrong time, and it will kill the yeast cells.

Yet salt is a must-use ingredient in baking. It gives your dough strength, allowing it to hold on to the gas bubbles that yeast cells produce as they feed on the flour’s sugars and starches.

There’s no need to worry about mixing yeast with salt and sugar if you’re using instant yeast. That’s one of the reasons why instant yeast is my favorite type of yeast in the first place.

However, if you’re using fresh yeast or active dry yeast, you should proof it before mixing it with the flour and salt. That way, you protect the perishable yeast cells from the aggressiveness of the salt.

Oh, and just one more thing. When it comes to baking, one thing you’ll notice as you read more bloggers and watch TV or YouTube chefs is that there is no right and wrong.

Though baking science is the same for everyone, each and every baker (professional or home cook) tends to have their own technique.

What is yours? Share your best tips and tricks for using yeast and salt for baking in the comments below.