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Sourdough Smells like Vinegar – Why? Safe to Eat?

People who have delved into the world of sourdough-making know that especially when you’re just starting out, sourdough can smell of a lot of things – stinky feet, vomit, and bad cheese just to name a few of the more interesting odors. It can also smell like alcohol, nail polish remover, and even vinegar.

When this happens, rarely does it mean that your sourdough has turned evil, unless you see obvious bad mold. It does mean, however, that your sourdough starter, due to an imbalance in the system, is producing more of a specific type of compound, giving it its smell. 

Why does this happen and what compound is involved if your sourdough smells like vinegar?

Why Does Sourdough Smell Like Vinegar?

Sourdough that smells like vinegar is due to a starter that is producing too much acetic acid. A sourdough starter should have a yeasty, slightly sour smell that is pleasant. If it has a vinegar smell, it means the dominant bacteria has produced more acetic acid, due in part to lack of food. Try increasing your starter’s feedings and moving it to a warmer place to reestablish its balance.

Sourdough Smells like Vinegar - Why? Safe to Eat?
Sourdough Smells like Vinegar – Why? Safe to Eat?

My Sourdough Smells Strangely of Vinegar! What happened?

A strong vinegar smell in your sourdough bread is due to the overproduction of acetic acid by the lactic acid bacteria. 

While some amount of acetic acid is necessary, as it is what gives sourdough its characteristically tangy and sour taste and smell, too much of it can overpower your sourdough starter and make it quite unpleasant smelling.

But why does this happen?

A Starving Starter

A starter that smells of vinegar is likely very hungry and needs to have more food. In a system like a sourdough starter, the yeast and bacteria that dominate need to have a constant supply of food, otherwise, they will start consuming their waste products and spoiled or discarded yeast for sustenance. 

When this happens, it offsets the balance of the system and can produce unpleasant odors in your starter which can potentially impact your bread.

Cultures for Health is a one-stop resource for all things pertaining to fermentation, and when we asked them for the specific reason why sourdough starters can sometimes have a strange smell, like that of alcohol, nail polish remover, or vinegar, they helped shed light on what may be happening.

In an email, they told us that if a starter is smelling strange, for example, if it smells like vinegar, it is likely hungry and needs to be fed more.

When the starter isn’t fed enough times or you miss out on the feedings, the bacterial balance changes, as some bacteria thrive more in certain conditions over others, which leads to the starter producing an abundance of more things, in this case, acetic acid. 

Cultures for Health Says that if your starter smells of vinegar, it means that it is very hungry and has produced an excess of acetic acid. The bacteria have consumed all the flour nutrients and very much want to be fed.

So if your starter is starting to smell like you can use it for your salad dressing, the likely reason is that it is very hungry and needs to be fed more. Try increasing the frequency of its feedings to see if the smell dissipates eventually.

A sourdough starter that smells like vinegar likely needs to be fed more.
A sourdough starter that smells like vinegar likely needs to be fed more.

Try Moving It To A Warmer Place

Acetic acid is naturally produced during fermentation by lactic acid bacteria, and this can give your starter a vinegar smell because vinegar is essentially composed of acetic acid and water.

According to Serious Eats, there are two types of lactic acid bacteria. One that converts sugars to lactic acid only, and one that converts sugars to both lactic acid and acetic acid. 

The Lactic Acid Bacteria (or LAB) that produce just lactic acid are called homofermentative and prefer warmer temperatures, while the LAB that produces both lactic acid and acetic acid are called heterofermentative and thrive at much lower temperatures. 

If your sourdough starter smells of vinegar, it is possible that the heterofermentative bacteria are dominating. Acetic acid is naturally needed in any sourdough starter, as it is what lowers the pH considerably to ward off bad bacteria, and it is one that is responsible for the sour taste of your sourdough. 

Try moving your sourdough starter to a warmer area while increasing feeding to see if it changes the bacterial balance.

The intervals at which you feed your starter, the temperature, and the kind of flour, water, and ambient environment you have in your fermentation area influence the smells and textures that your sourdough starter will have, but in general, the first step is to always just try and feed your starter more.

What Is A Sourdough Starter?

A sourdough starter is a symbiotic and stable colony of wild yeast and good bacteria that is created through the fermentation of flour and water and is used for leavening and flavoring bread dough. It is a system that needs to be regularly maintained and fed so as not to disturb its balance.

The specific composition of yeast and bacteria in each starter is different; as the microbiome population would depend on the organisms present in the flour, the water, the air, the jar, geographical location, and some studies even suggest, the baker’s hands!

Each starter begins with a group of yeast and bacteria, and in a true reflection of the process of natural selection, the best, most resilient group of bacteria and yeast eventually dominates and gives the starter its unique microbial composition.

The specific strains may be different for each starter but in general, they are composed of wild yeast and lactic acid bacteria. The yeast is what is responsible for producing the carbon dioxide that is necessary to produce the airy, fragrant bread that is the stuff of every bread baker’s dreams.  

The lactic acid bacteria is the one responsible for lowering its pH and giving it that tangy, sour taste, and prevents bad bacteria from proliferating in the starter. 

The resulting colony, after the initial fight for dominance, produces something that is actively bubbly and rises when fed, and that has a pleasant yeasty and mildly sour aroma.

Once stabilized, each starter will develop its own characteristic smell. But during the initial process, it can range in smell from vomit to used socks, to stinky feet, spoiled milk, and bad-smelling cheese.

If the balance is not achieved, the sourdough starter may end up smelling like other things, too. A strong alcohol, nail polish, or vinegar smell indicates that there is an imbalance going on in the colony. 

The type of bacteria and yeast that dominate in a starter depends on the frequency of feedings, type of flour, water, and temperature of the environment.
The type of bacteria and yeast that dominate in a starter depends on the frequency of feedings, type of flour, water, ambient environment, and even the baker’s hands.

What Can I Do With A Starter That Smells Of Vinegar?

A sourdough starter that smells like vinegar can often be saved by increasing the number of times it is fed. Cultures for Health mentions though, that if a starter has been neglected for a long time, it will take more time to wake it up and establish the correct balance in the system.

Patience and consistency are key; you just need to keep feeding it until it reestablishes its own balance. According to experts, sourdough starters are pretty resilient, and do not die easily. Most of the time, increased feedings should do the trick.

If for some reason, increasing the feedings do not do anything for the starter, Cultures for Health had this to say:

Remove 2 tablespoons of starter and feed with ¼ cup water and a ¼-½ cup of flour. When it is time to feed the starter again, resume normal feeding amounts.

– Cultures for Health

By diluting and introducing a new group of bacteria to populate the starter, you give your sourdough a fighting chance to regain its natural state of balance.

How Do I Know When It’s Time To Toss My Sourdough Starter?

Increased feedings will usually fix sourdough starter that has a strong alcohol, nail polish remover, or vinegar smell.

But if you see something pink or orange in your starter or you see signs of visible mold, it is a sure signal that bad bacteria have taken over your sourdough starter, and sadly, the good bacteria lost.

Also, if your sourdough starter doesn’t respond even after feeding, it is likely a goner at this point. When this happens, it is best to just toss it and start over. 

Is Sourdough That Smells Like Vinegar Safe to Eat?

Sourdough that smells like vinegar is safe to eat. Usually, the smell will bake off as you make your bread but if it lingers, it should still be safe to eat.  Some people actually prefer their sourdough bread to be more sour than others, and if that is you, then this may even be an ideal situation for your taste buds.

According to Cultures for Health, you can actually manipulate how sour your sourdough bread will be by adjusting the conditions of your starter environment, and how you rise and ferment your bread.

Organisms that produce acetic acid thrive in drier, cooler environments, and prefer whole-grain flours. Introducing these aspects to your starter as well as how you rise your dough will produce a product that’s more sour and tangy. 

On the flip side, organisms that produce lactic acid, the one responsible for giving it that pleasantly yeasty, yogurt-like smell, thrive in more wet and warmer environments.

Manipulating your sourdough starter conditions like this can help you adjust the flavor of your dough. If you dislike bread that’s too sour, there are things you do to offset some of that sourness.  

You can manipulate the conditions where you keep your starter or ferment your sourdough bread to make it more or less sour and tangy.
You can manipulate the conditions where you keep your starter or ferment your sourdough bread to make it more or less sour and tangy.

What is Sourdough Bread?

Sourdough is a type of bread that is naturally leavened with wild yeast and bacteria through a “starter” made by fermenting flour and water.

Unlike regular bread that uses commercial yeast to rise, sourdough relies on natural, wild yeast and the good bacteria produced during the fermentation process to get its rise. It contains no additives and relies on the natural process of fermenting to achieve its characteristically tangy flavor and chewy texture.

Especially if you’re just starting out and making your own starter, sourdough can take a lot of time and patience to make.

There are lots of resources and guides available out there to help you get started.  However, it would also take a lot of intuition and observation on your part because your sourdough starter will be unique and have a unique set of circumstances that can influence how it develops.

Is Sourdough Healthy?

Sourdough is typically healthier than other types of bread for several reasons.

Naturally leavened

Sourdough is said to be healthier than regular white bread as it is naturally leavened and does not use commercial yeast and additives typically found in store-bought bread.

Fiber and Digestive Health

Especially when made with whole wheat flour, sourdough contains fiber that helps with digestive health. During fermentation, sourdough contains a lot of probiotics, but not many of those survive the baking temperatures.

However, the prebiotics it contains does survive, and help feed the existing good bacteria in our guts that help facilitate and maintain the health of our guts.  

Increased Bioavailability

The lactic acid in sourdough bread also helps make the vitamins, minerals, protein, and other nutrients present in sourdough bread to become more bioavailable, or more absorbable by the body.

This then makes the nutrients more useful to our bodies. This process happens during the fermentation process through the breakdown of the phytic acid, which normally inhibits the absorption of vitamins and nutrients.

May Help Manage Blood Sugar Levels

Sourdough is also said to have a low glycemic index, which means that it doesn’t cause blood sugar to spike as it is absorbed slowly by the body. As such, it helps to manage blood sugar levels, unlike regular white bread. This is especially beneficial for those who need to watch the levels of sugar in their blood.

Less Gluten and More Digestible

Because of the slow and long fermentation process, sourdough contains less gluten than regular bread, and is, therefore, gentler on the digestive system. In one study, it has been found that sourdough bread is more easily digested by the body compared to regular bread.

The fermentation process is really what makes sourdough a better choice for bread, health-wise, as it offers our bodies more available nutrients that it can use to promote health and well-being.

Sourdough is healthier than other types of bread.
Sourdough is healthier than other types of bread.

Is Sourdough Gluten-Free?

Sourdough has a naturally tangy flavor and because it is slow-fermented, is touted by many to be superior to other types of bread in terms of health benefits.

For those who have trouble with gluten, sourdough is thought to be a more digestible alternative as because of the long fermentation process, the gluten is broken down into a more digestible, absorbable form, minimizing the discomforts it usually brings about in its usual form.

Sourdough has less gluten than regular bread and because it contains good bacteria that aid the gut in its digestion, it becomes easier for the body to digest and becomes even easier to enjoy.

While it may be easier to digest and may have less gluten than regular bread, it is important to keep in mind that sourdough is not gluten-free unless it is made with a gluten-free starter. If you have gluten allergies or sensitivities or if you have celiac disease, it is important to remember this.

According to Beyond Celiac, even if it has less gluten, it still does not reach the amounts required for it to be considered gluten-free. And even if someone who has a sensitivity to gluten does not exhibit symptoms by consuming sourdough bread, there is still the possibility that the damage could still be happening inside the gut.

As such, it is important to keep in mind that when serving to people who have gluten allergies or sensitivities, to make sure that you are using certified gluten-free products.

Frequently Asked Questions to Sourdough Smells Like Vinegar

What Should My Sourdough Starter Smell Like?

Sourdough starters should have a smell that is a mix of a pleasantly yeasty smell with a slightly tangy and sour smell. If your starter does not smell like this, try increasing your feedings to help the system balance itself out.  

My Sourdough Starter Smells Awful. Should I Carry on or Toss it Out?

Sourdough starters, especially in their infancy, can go through bad and unusual smelling phases and can smell oddly of used socks, vomit or stinky cheese. The key is to keep feeding your starter until a pleasant mix of bacteria and yeast dominates, and when this happens, the smell should improve.

Why Does My Sourdough Smell Like Vinegar?

A sourdough starter that smells like vinegar is a starter that has an overabundance of acetic acid due to the starter not having enough of a food source. In the absence of food, yeasts and bacteria metabolize their own waste products and try to adapt to their surroundings, resulting sometimes in strong smells like vinegar. Increased feedings should help correct the situation.

Conclusion to Sourdough Smells Like Vinegar

Sourdough that smells like vinegar was likely made with a starter that has an overabundance of acetic acid, the compound that makes up vinegar.

This happens mainly because of feeding and temperature conditions of the fermented starter, which encourage lactic acid bacteria that produce acetic acid to thrive more than the other type of bacteria.

This results in bread that smells like vinegar, and can be more sour and tangy than a starter that does not have too much acetic acid.

It is safe to eat, but if you prefer your sourdough to be less tangy and sour, you can opt to correct and adjust the conditions of your starter to tame the production of acetic acid. This is usually done through increased feedings and moving your starter to a place with a warmer temperature.

Author Bio

Daniel Iseli (Head Chef)

Hi, my name is Daniel and I am passionate about cooking. I have been cooking for the past 20 years and am happy to share my best recipes and cooking-related knowledge with you.