My kids and I are big fans of the television show “MythBusters,” where the hosts use science to prove or disprove myths, such as: Can a pressurized can of refrigerated biscuit dough explode in a hot car? And what really happens when you mix Pop Rocks and soda?
Following in their footsteps, I’m here to answer a common baking question: Does salt kill yeast?
Photography by Rick Holbrook; food styling by Kaitlin Wayne
If you’ve done some bread baking, you’ve probably encountered a warning about how you should never let salt and yeast come in direct contact because “salt kills yeast.”But is it true?
Salt is hygroscopic, meaning it readily absorbs water from its surroundings. If a large amount of salt (or sugar, which is also hygroscopic) were to be combined with a small amount of yeast and left for a long time it could, in theory, eventually rob the yeast of water to the degree that the yeast cells would begin to die off. Director of Research & Development Sue Gray explains, “If you added a large amount of salt, say a tablespoon, to a 1/4 teaspoon of yeast and let that sit for a while it could have a negative effect, but not in the concentrations we use in baking.” In most recipes, salt represents 2% of the total mix (based on flour weight), a low enough percentage that it would never kill the yeast present in the dough. Plus, they’re not going to be in direct contact for long; usually, it’s just a few minutes between combining ingredients and mixing your dough.
So, while it’s theoretically possible for salt to kill yeast, practically speaking it’s not a concern; you can let them touch without any negative effects.
Photography by Mark Weinberg; food styling by Liz Neily
That’s not to say that salt has no effect on yeast at all; it certainly does. Salt acts as a yeast inhibitor, slowing growth and reproduction of yeast in bread dough. That might sound detrimental, but it’s actually desirable, helping keep the yeast growth in check so your dough ferments at a controlled rate. (The presence of salt also positively contributes to yeast dough by strengthening its gluten network and aiding with crust browning — read more about this in our blog, Why is salt important in yeast bread?)
What’s more, adding hygroscopic salt (or sugar) to yeast doughs prompts the yeast cells to release some of their water through their cell walls, causing them to dehydrate and shrink. This osmotic shock to the yeast cells results in a brief “lag phase” where the yeast doesn’t do much of anything. But the yeast can handle this shock, recovering quickly and entering the “expansion phase” where it begins to produce carbon dioxide that causes dough to rise.
But the main takeaway here: In any normal, practical scenario where a baker would be combining yeast and salt, there is no chance that allowing the two to touch — or mixing them together — would cause the yeast to die. This myth? Busted.
Salt acts as a yeast inhibitor, slowing growth and reproduction of yeast in bread dough. That might sound detrimental, but it's actually desirable, helping keep the yeast growth in check so your dough ferments at a controlled rate.
Saying that, the simple act of mixing salt and yeast in water does not cause such extreme osmosis that the yeast gets dehydrated and dies instantly. Ok, if you'd mix an unreasonably large amount of salt with yeast and leave them to sit together for an unreasonably long time, then perhaps.
Salt slows down fermentation and enzyme activity in dough. The salt crystals draw water away form their environment (salt is 'hygroscopic'). When salt and yeast compete for water, salt wins and the yeast is slowed down.
But what this test also shows is that bakers still shouldn't worry about this rule, at the most common levels used to make bread, salt does not kill yeast. And further than that, it doesn't matter one bit how you mix the two together.
Salt has a retarding effect on the activity of the yeast. The cell wall of yeast is semi- permeable, and by osmosis it absorbs oxygen and nutrients, as it gives off enzymes and other substances to the dough environment. Water is essential for these yeast activities.
So, while it's theoretically possible for salt to kill yeast, practically speaking it's not a concern; you can let them touch without any negative effects. Our back-of-the-bag oatmeal bread is a simple loaf that's made by mixing everything, including the yeast and salt, together.
While sugar and other sweeteners provide "food" for yeast, too much sugar can damage yeast, drawing liquid from the yeast and hampering its growth. Too much sugar also slows down gluten development. Add extra yeast to the recipe or find a similar recipe with less sugar. Sweet yeast doughs will take longer to rise.
To activate dry yeast, you'll need to leave it in a bowl of warm water (100–110℉) mixed with a pinch of sugar for 10–15 minutes. You can also use warm milk if you nix the sugar. Yeast is used in baking as a leavening agent, meaning it makes cakes and bread rise.
Thanks to its natural role in the fermentation process, yeast has been used as a safe ingredient for making bread, beer and wine for centuries. More recently, yeast has been put to use as a beneficial and safe probiotic. Reading time: 2 min. Yeast occurs naturally and has been used for millennia in our food.
Apple cider vinegar (ACV) has been found to inhibit the growth of Candida albicans, the strain of fungi that typically causes yeast infections. To use this natural remedy, mix 1 spoonful of ACV into a glass of water and drink every morning.
The best treatment to get rid of most yeast infections comes down to medicated creams or a pill. Studies show that treatment with either vagin*l cream or an oral pill, fluconazole, works more than 90% of the time. Uncomplicated vagin*l yeast infections usually respond to treatment within a couple of days.
Although they may seem convenient, the scientific evidence for their use is lacking. Common alternative treatments for yeast infections include apple cider vinegar, coconut oil, tea tree oil, garlic, cranberry juice, plain yogurt, and probiotic supplements. Consult a healthcare provider before using a home remedy.
Halotolerant yeasts have been described as being able to grow in the presence of salt concentrations as high as 4 M NaCl [3,4]. Nevertheless, yeasts can survive higher salt concentrations [5].
Too Hot to Survive. Regardless of the type of yeast you use, if your water reaches temperatures of 120°F or more, the yeast will begin to die off. Once water temps reach 140°F or higher, that is the point where the yeast will be completely killed off.
So, to avoid this error, get into the habit of always weighing out your yeast separately to your salt and adding them separately to the bowl. Without water, dried yeast will not absorb the salt, but by developing this habit you'll ensure you don't inadvertently kill your yeast when you add in the water.
In the first few minutes of baking, in a hot oven, the yeast gives its all to produce a surge of leavening. This final expansion of the dough is called “oven spring.” After about 5 minutes, when the dough reaches 140ºF, the yeast is killed and no additional leavening gas is produced.
When to Use Unsalted Butter. Butter without salt should be your go-to choice for baking and making pastry and can be used anytime fat needs to be added to a recipe. It is especially important in yeast doughs because too much salt can kill yeast in bread and leads to improper leavening.
This can affect the bread by adding a "yeasty" taste if you put too much into the dough. General amounts of yeast are around 1 - 2 % of the flour, by weight. Too much yeast could cause the dough to go flat by releasing gas before the flour is ready to expand.
Introduction: My name is Jonah Leffler, I am a determined, faithful, outstanding, inexpensive, cheerful, determined, smiling person who loves writing and wants to share my knowledge and understanding with you.
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