The main thing that makes sourdough bread possible are the bacteria that live in the sourdough starter, so it’s perfectly normal to ask yourself if sourdough bread is safe, as we are used to associating bacteria with bad things. But you can rest easy, sourdough bread is completely safe.
Sourdough bread is safe to eat, the bacteria found in the starter are not harmful and don’t survive the baking process. The sourdough starter also has a very acidic environment that makes it extremely difficult for bad bacteria to develop, thus making sourdough bread very safe.
As we all know there are different types of bacteria, some of them are good for us and some of them are bad for us, sourdough bread relies on good bacteria to make the bread grow and make it healthy. So let’s see what kind of bacteria sourdough has.
The Bacteria That Live in Sourdough
Right from the start, I want to make it clear that the bacteria we are talking about are found in the sourdough starter, not the bread, during the baking process the bacteria are destroyed by the intense heat. If your bread spends a few minutes at 212°F (100°C) the bacteria will disappear completely. And considering that bread is baked at much higher temperatures, there is no reason to worry.
But bacteria is a very broad word that can easily make you think about bad things. The bacteria inside sourdough care are called probiotics, which are also naturally found in our gut, and they do a lot of good things for us.
Here are some of the things that probiotics (the good bacteria) do in the sourdough:
1. Probiotics Produce Lactic Acid
Lactic acid is what makes sourdough sour, and it’s also what gives sourdough bread its long shelf life and prevents the starter from molding.
The lactic acid is produced by the probiotics as a byproduct when they consume the sugar and starch found in the flour.
There are also quite a few health benefits that lactic acid provides, the most important being:
- Improving the gut health
- Boosting the nutrient absorption rate
- Acting as an antioxidant
- etc.
The lactic acid also makes the sourdough starter extremely resistant to bad bacteria that can’t survive in the acidic environment. And it also makes sourdough bread last longer than any other bread.
2. Probiotics Decrease the Phytic Acid Present in Wheat
Phytic acid is known as an anti-nutrient because it impairs the absorption of nutrients, like iron, zinc, and calcium.
Phytic acid is naturally found in grains and plant-based foods, so all types of bread contain some amount of phytic acid, it’s not something specific to sourdough, on the contrary, sourdough bread contains less phytic acid than other types of bread.
The probiotics found in sourdough drastically reduce the amount of phytic acid, thus making sourdough bread considerably richer in nutrients.
3. Probiotics Lower the Glycemic Index of the Bread
All flour contains small amounts of sugar which increases the glycemic index. But because the bacteria and yeast in the sourdough consume the sugar in order to grow, the glycemic index of sourdough bread is considerably lower than any other type of bread, and the sugar levels in the blood will remain steadier.
4. Probiotics Pre-digest the Flour
While not the most appealing fact about sourdough probiotics, it’s actually one of the main advantages.
In order to survive probiotics need to eat, in the case of sourdough they eat the flour. So basically sourdough is pre-digested, which makes it easier for our stomachs to digest it, as some of the work has already been done.
If you want to know more about the probiotics in sourdough bread you can check out my article: Does Sourdough Contain Probiotics?, in this article, I discuss the many advantages of probiotics, how they work, the different types of probiotics that a sourdough contains based on the floor that was used and many more, so if you are interested, make sure to check it out after finishing this one.
Signs That the Sourdough Has Gone Bad
But despite all the natural self-defense mechanisms sourdough has against bad bacteria and other harmful things, there are times when a sourdough starter or a sourdough bread can go bad.
Here are the most common things that you will see if your sourdough has gone bad:
- Mold. If you see mold on your sourdough starter, or on your sourdough bread, it’s time to throw it away.
- Bread Not Rising. No sourdough bread will rise if the starter has gone bad.
- A Pink or Orange Tint. If your starter has a pink or orange tint to it, it has definitely gone bad and is time to throw it away.
- No Bubbles in the Starter. If you regularly feed your starter but you don’t see any bubbles it means that the good bacteria, the probiotics, have disappeared and the only things that can be found in the starter are now harmful.
In general, I would say that what applies to any bread also applies to sourdough bread. So if you notice that the taste has drastically changed, and not in a good way, your sourdough might have reached its expiration date. Or it started smelling weird, it might be because it’s over its shelf life.
Sourdough bread has a shelf life of about 5 to 6 days, which is considerably longer than most homemade bread. But there are a lot of factors that can drastically reduce that shelf life, for example, heat and humidity. So I would say that you shouldn’t eat sourdough bread that is older than 5 days. (In this article I will also address keeping sourdough bread in the fridge, but just to reduce the suspense I will tell you right now that it’s not a good idea)
Fake Signs That the Sourdough Has Gone Bad
There are a few misconceptions out there that made people throw out their perfectly good sourdough bread and starters.
While there is nothing bad in not wanting to take any risk (I actually advise you to do this when it comes to food), you shouldn’t throw out a perfectly fine sourdough just because you didn’t know what was happening.
Here are some normal things that happen with sourdough that people mistakenly think it went bad:
- Sour or Sweet Taste. As the name implies, sourdough bread is usually sour. But depending on how much the sourdough had risen before the baking the taste can drastically change from slightly sweet, to very sour. So taste is usually not a good way to see if the sourdough bread has gone bad.
- Liquid at the Top of the Starter. This is a very common thing to happen to a starter and it’s not a bad thing. It’s actually a sign that you should feed your starter more often. But the starter itself, while a little hungry, it’s perfectly fine, and not harmful in any way.
- Very Pungent Smell. Sourdough starters can develop a very wide range of smells, ranging from sweet, to vinegar-like, to smelly feet, to nail polish. All those smells are perfectly normal for a sourdough starter, and they can easily change from one day to another.
How to Maintain a Healthy Sourdough Starter
Maintaining a healthy sourdough starter is important for two reasons.
The first one is the taste of the bread. A well-maintained starter will give you a much tastier bread than a poorly maintained one.
The second is that a healthy sourdough starter will keep the bad bacteria out. So let’s see how to maintain a sourdough starter healthy.
- Keep a consistent feeding schedule. Try feeding your starter the same amount at the same time every day.
- Use the same flour every time. While it’s possible to change the flour, it will require about one week for the starter to get used to the new flour and during that time it will need some time to adjust to the new flour, during which time it will be vulnerable to bad bacteria.
- Feed your starter exact measurements. Sourdough starters are quite sensitive so it’s important to feed it exact measurements every time, so use a digital scale and weigh your water and your flour.
- After adding the flour and water, mix everything very well. Mixing everything together will allow the good bacteria to have access to all the food that you are giving them. But just as important is the air that enters in the mix, so make sure to give it a vigorous mix.
- Make sure that there is enough space in the jar. If there is not enough space in the jar the starter will spill all over the place, this will make a mess as well as make the starter come into contact with a lot of bad bacteria.
- Don’t tighten the lid of the jar. This is not necessarily related to bad bacteria or anything of the sort but is related to safety. If the carbon dioxide that forms has nowhere to go it will eventually make the jar explode.
Is It Safer to Store Sourdough in the Fridge?
In the case of sourdough bread, you shouldn’t. But in the case of the sourdough starter, you can do it.
Keeping your sourdough starter in a fridge is perfectly safe. I would actually recommend you to do so if you are not using it regularly.
Due to the low temperature of the fridge, there is a lower chance for bad bacteria to develop, but the sourdough already has enough protection against it. So if you were thinking of keeping your sourdough in the fridge just for this, you shouldn’t bother.
The low temperature of the refrigerator will drastically reduce the activity of the sourdough, which means that it doesn’t have to be jeed as often, but also that it won’t be at its maximum potential when it’s time to make some bread.
This is why I would advise you to remove your sourdough from the fridge at least one week in advance before making any bread with it.
In the case of sourdough bread, I would advise you not to keep it in the fridge, while it’s not unsafe, it will make the bread last fewer days as it will dry out quicker, and it can make it smell strange, as bread has a tendency of absorbing the smells in its surroundings.
For storing sourdough bread I would recommend a breadbox or a plastic bag. Using those methods the taste of your bread won’t change and it will stay fresh for 5 days easily.
If you want to keep your sourdough bread for longer there is a simple way, put it in the refrigerator. As strange as it might sound it actually works, and if you do it the right way there will be no loss in taste or texture, and it will easily last for up to three months.
If you want to know how to do this check out my article: How to Freeze Sourdough Bread Without Losing Taste or Texture, there I describe step by step my true and tried method that I’ve been using for years with excellent results every time.
Final Thoughts
As you can see sourdough bread is completely safe, I would actually say that it’s safer than most types of bread out there due to its high resistance to bacteria.
The part that you might have heard about bacteria living in sourdough is completely true, but the bacteria are found in the starter, not the bread itself. And the bacteria we are talking about are called probiotics which are a good type of bacteria that can be found in our gut.
The sourdough starter is also very resistant to bad bacteria due to its acidity, and while it does require some maintenance, all this effort will pay off in the form of a tasty and healthy bread.
So if you were looking to find out if sourdough bread is safe, you can now rest assured knowing that sourdough is one of the safest types of bread out there.