Can Sourdough Starter Go Bad in the Fridge?


All the stay-at-home orders of the past two years have given rise to a lot of new bread bakers. After all, what better way is there to occupy an excess of free time than by learning to make perfect fresh bread? 

If you fall into this category, you may have suddenly found yourself making and needing to maintain a sourdough starter.  Or perhaps you’ve been passed down a sourdough starter that a family member has kept alive for years. How long can you really keep your starter and how do you ensure its long lifespan?

Sourdough starter has a very long lifespan and can be kept for years in the fridge if it is regularly fed and maintained. It can go bad if ignored and left unfed for long periods of time. Bad sourdough starter should be discarded and remade from scratch.

The older that a sourdough starter is, the more impact it will have, meaning that you will have more flavorful bread. A bread baked from a fresh, young sourdough starter will have a much milder taste than a bread baked from a starter that’s been fermenting for a while. 

This is definitely a good incentive to take care of your sourdough starter and keep it alive for as long as you can and we are here to help you do that!

How Do I Know If My Starter Is Bad?

Sourdough starter is something that requires your regular attention because it needs to be fed to encourage the growth of yeast and not bacteria.

 If you have a starter that you’ve forgotten about for some time there is a large likelihood that it has gone bad. Here are some signs to look out for to know for sure. 

Mold is usually a universal indicator that something has gone bad and the same applies to sourdough starter. If you begin to see orange or pink streaks or patches you should assume the starter has spoiled and get rid of it. 

The general color of your starter should also be paid attention to. A healthy starter is a grayish-white color (the color you would expect from mixing flour and water together) and the presence of any other colors can be considered alarming. You definitely don’t want to use a starter with any traces of pink, orange, or blue.

If your starter is not fed consistently it may develop a gray liquid on top. This liquid is referred to as “hooch” and is quite a normal occurrence. It is not immediately an indication that your starter is spoiled, just that it needs a little more attention.

If the color changes to a darker gray or brownish color it doesn’t necessarily mean your starter has gone bad, just that it needs to be fed more regularly.

However, if you start to notice bright colors like pink or orange in the liquid or it turns completely dark brown you need to throw your starter away. 

The smell of your starter can also indicate its health. A slight odor is normal for sourdough starter but once it starts to smell like something you can only describe as moldy or foul then you can assume your starter has gone bad. 

Tips for Storing Sourdough Starter Long-Term

There are many methods for safely storing sourdough starter that depend entirely on your personal preferences and the frequency with which you bake.

I’m offering you some of the most basic tips that are useful for beginners, but maintaining a starter (or more) is something that becomes an easy part of your routine the more practiced you become in it and once you figure out what methods work best for you.

If you are consistently baking a lot of bread a few times a week, your starter will be best kept at room temperature so that it is actively ready whenever you need it. In this case, you should be feeding your starter every twelve hours or so and keep it in a glass container with a breathable lid covering it.

Your starter can also be kept in the fridge if you bake only weekly or monthly. By keeping your starter in the fridge in a tightly sealed container, you reduce the need for daily feeding to a weekly feeding. This method requires some extra preparation for when you are ready to bake because you can’t use your starter right out of the fridge.

With a less frequent feeding schedule, it’s quite easy to forget to feed it but there is no need for alarm. If you skip a feed or two, you should still be able to salvage your starter by increasing the frequency of feeds.

A mature starter can generally last up to 2 months unfed in the fridge but a starter left neglected for too long will start to develop the problems I mentioned previously and may become unusable.

Freezing sourdough starter is also a viable option if you plan to be away from home for several weeks or don’t intend on using it for a long period of time for whatever reason. No preparation is needed for this method, just make sure you are using a freezer-safe bag or container. If stored well, your starter can be kept in the freezer for up to a year.

To use your starter again you will need to take it out of the freezer and discard half of it then thaw it at room temperature and feed it as it thaws. This may take anywhere from 2 days to a week. You will know your starter is ready to use when it begins to grow at a stable rate.

The last common option for storing sourdough starter for a long time is to dry it. To dry your starter you need to prepare it as if you were going to bake with it. Make sure it is fed and active. Then spread it as thinly as possible onto a sheet of parchment then leave it out to dry completely.

Drying your starter can take anywhere from a day to 5 days depending on the climate and conditions of your space. You can also dry out your starter in the oven if the air in your kitchen is too humid but do not turn the heat on. Simply put on the fan or your oven’s electric light to produce a gentle heat.

Once your starter is completely dry, break it up into pieces and store it in an airtight container or glass jar at room temperature, somewhere where it is not exposed to high heat or sunlight. You will need to revive your starter with lukewarm water and flour once you are ready to use it again.

Can Eating Bad Sourdough Starter Make You Sick?

Sourdough starter relies on the development of good bacteria through fermentation. The more time this bacteria has to develop the more flavor it will bring into your bread. But in order for the bacteria to stay healthy, it has to be well maintained. Neglected starters will easily provide an environment for the rise of harmful bacteria.

Consuming any bad bacteria is never a good idea.

Will it kill you or make you really sick? That’s unlikely, especially since you will have baked it through and thereby lessened some of the harmful properties, but the resulting bread will not taste or smell right and be unpleasant to eat.

If you notice any of the changes I mentioned above you should get rid of your starter.  Throwing away something you’ve worked for months or years to maintain can be frustrating but it is much better to be safe than sorry.

Why Does My Sourdough Starter Smell So Bad?  

A slight odor is normal for sourdough starters. It indicates the presence of good bacteria that keep it going. A strange, tangy smell is normal for a starter but when a starter goes bad its smell gets worse. 

The smells that are typical for a sourdough starter are sweet and vinegary. A young starter will smell slightly sour like yogurt because it contains lactic acid. 

If your starter has been around long it will have gone through a fermentation process that produces acetic acid which will have a sharper smell similar to acetone. 

Neglected sourdough starters will start to accumulate too much acidity. You can usually mitigate this by feeding your starter more rigorously if you’ve left it unfed for too long.

 However, if the smell your starter gives off becomes really foul and sharp like vomit or old sweaty clothes, it is probably best to discard it and start again from scratch. 

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Robin

Robin is in his 30s and still enjoys the things he enjoyed as a teenager. He has studied nutrition, personal training, coaching, and cooking. He has an ever-growing interest in the art of cooking the best burger in the world. Thankfully, he also loves going to the gym.

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