How Long Does Sourdough Discard Last?

Maintaining a sourdough starter means you will have a constant supply of leftover sourdough discard that must be tossed or saved and used for other recipes. If you decide to save your sourdough starter, how long will it last?

For thousands of years, sourdough bakers have been maintaining sourdough starters in order to bake loaves of bread with delicious sourdough flavor. Sourdough starters contain a combination of wild yeast and bacteria that take the place of commercial yeast from the grocery store.

It is the presence of these naturally occurring yeasts and bacteria that help sourdough bread rise and give it a sour taste.

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What is Sourdough Discard?

Sourdough discard is the part of your active starter that you usually throw away when you feed it. It is also known as unfed starter. 

It is less bubbly than an active sourdough starter and is not strong enough to make bread dough rise. But that does not mean it should be thrown away.

Sourdough discard is typically runnier than sourdough starter because it has consumed all of its food and has started to break down.

Sourdough starter can be saved and used in sourdough discard recipes. It is an easy way to add tons of incredible flavor to baked goods. The lactic acid found in sourdough discard adds flavor and helps to tenderize wheat proteins.

Because sourdough discard doesn't have the same rising power as a fresh sourdough starter, it is often used in quick breads that utilize a small amount of additional leavening agent such as baking powder and/or baking soda for additional lift.

Some of my favorite sourdough recipes include sourdough flatbread, sourdough discard banana bread, sourdough sugar cookies, and these sourdough blueberry and fresh thyme scones.

How to Store Sourdough Discard

Many bakers will use their sourdough discard right away. But in an effort to reduce waste and the amount of baking I must do on a daily basis I maintain what is known as a micro sourdough starter.

This means when I refresh my starter by feeding it I am only adding 20 grams of starter to my discard jar. This amount of discard isn't enough discard for most recipes.

Each day I save my discard in an airtight container until I have enough for the sourdough discard recipe I want to make. Sourdough discard will last at room temperature for a couple of days.

Check this post out for more information on choosing the perfect container for your sourdough starter and discard.

There are other storage options mentioned below that will allow you to save your sourdough discard for longer.

Does Sourdough Discard Need to be Refrigerated?

Refrigerating sourdough discard basically puts it to sleep and dramatically slows down the fermenting process.

I typically store my discard in the refrigerator. I keep it in a quart canning jar that is loosely sealed with a reusable lid. I prefer wide-mouth canning jars because they make it easier to add and remove discard.

I try to use my refrigerated sourdough discard within a week or two but you can probably store it in the refrigerator indefinitely. However, the quality and flavor of the discard will change and deteriorate over time.

Can I Add Discard From Different Days to the Same Jar?

Yes, actually adding fresh discard to a jar of older discard is a great way to lengthen the amount of time you can store it.

Can You Freeze Sourdough Discard?

The best way to store discarded starter for longer periods of time is to freeze it.

For the best results, I recommend freezing it in one cup quantities. Frozen sourdough discard can be kept for a long time but you should always be on the lookout for freezer-burn which can reduce its quality.

Does Sourdough Discard Spoil?

As sourdough discard ages it will become sourer and sourer and have a strong acetone smell similar to nail polish remover. It will also produce a clear liquid on top known as hooch.

Hooch is an alcohol by-product of the fermentation process and is an indicator that your discard is hungry. Sourdough discard in this state is still ok to use, just stir the hooch back in.

But remember the older discard is the stronger its flavor will be. A strongly flavored discard is probably not best for a sweet sourdough recipe. Fresh sourdough discard won't be as acidic and will have a milder flavor.

One of the most common strains of bacteria found in sourdough starters is Lactobacillus. This strain of bacteria produces lactic and acetic acid which gives sourdough its characteristic sour flavor.

Lactobacilli is also necessary to maintain the health of your sourdough starter and its discard. It produces an antibiotic that protects your starter from the invasion of other bad bacteria.

You will know these harmful bacteria are present if you see streaks of color in your sourdough starter or discard. If this happens you will need to throw it away.

How do You Know if Sourdough Discard is Bad?

As mentioned above if you see any visible mold aka fuzzy spots on your sourdough discard, throw it away. You might only see mold on the top and think your discard is still ok to use if you scrape away the visible mold but this isn't the case.

By the time you see visible mold, the mold spores have spread throughout your sourdough discard.

Can Old Sourdough Discard Make You Sick?

Yes, consuming mold can cause a variety of illnesses. You wouldn't eat a moldy strawberry so don't eat moldy sourdough discard. And no even if you bake it moldy sourdough discard is still not safe to eat.

Can Sourdough Discard be Used to Make a New Starter?

Yes! Freshly discarded sourdough starter can be fed and shared with a friend to start their own sourdough baking journey.

Simply take a portion of your sourdough discard and add it to a clean jar. Add equal parts of flour and water and stir together. For example 30 grams of discard + 30 grams of flour + 30 grams of water = a new sourdough starter.

What is the difference between sourdough starter and sourdough discard?

Sourdough discard is actually my favorite part of maintaining a sourdough starter. It is so versatile and can be added to so many recipes. Save your discard so that you can enjoy one of the recipes listed below and put it to good use.

• Sourdough Discard Apple Cinnamon Muffins
• Flour Tortillas Made With Sourdough Discard
• Sourdough Crackers

If you are new to sourdough, I've created a sourdough gift guide that lists all of my favorite sourdough products.

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