Sourdough Discard 101

The term “sourdough discard” is a bit of a misnomer. Discard implies waste or trash, but sourdough discard is an incredibly versatile and useful ingredient that can reimagine how you cook or bake with your starter!

I use sourdough discard in a trove of sourdough discard recipes and keep a weekly stockpile of it in my refrigerator just for the purpose of baking with it. You can use it in savory or sweet applications.

This comprehensive guide on sourdough discard covers what sourdough discard is, how to store discard, how to bake with it, the differences between discard and levain, and other frequently asked questions about sourdough discard.

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What is Sourdough Discard?

Each time you feed your sourdough starter, you must remove some of it.

Why? Because a healthy sourdough starter will quickly outgrow its container and get too large! Soon enough, you’ll be overflowing with sourdough starter.

Sourdough discard is the portion of sourdough starter removed before refreshing or feeding your sourdough starter.

In other words, sourdough discard is an overripe sourdough starter often thrown away or tossed to control the starter’s size and acidity.

Some refer to sourdough discard as “sourdough surplus” because it doesn’t have to be wasted as the word “discard” implies.

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What’s the Difference Between Sourdough Starter, Discard, and Levain?

The differences between sourdough starter, discard, and levain are subtle but important.

Sourdough starter is the mother culture. It is refreshed and fed regularly. The mother culture lasts indefinitely with routine care, and its main use is the leavening in a recipe.

Sourdough discard is an unfed, ripe portion of the mother culture. You remove the sourdough discard during feedings to maintain the size of your sourdough starter. Trash discard or store it to use as an acidic ingredient in unleavened recipes.

Finally, a levain (luh-VAHN) is an offshoot of the mother culture. Feed the levain separately from the sourdough starter and use 100% of it in a recipe.

I start most of my leavened recipes with a levain so I can feed my small starter on its same routine and build a separate larger culture for the recipe. Furthermore, you can feed the levain with other flours or ingredients without disrupting the balance of the mother culture.

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How to Reduce Sourdough Discard

The amount of discard created from a starter varies. The quantity of discard depends on the size of the starter and how you regularly feed your starter. I always recommend a regular feeding schedule to keep your starter healthy and active.

A large starter will result in more sourdough discard. Likewise, a small sourdough starter will result in less discard.

I create and maintain a small sourdough starter, which reduces waste. This minimizes the amount of discard I throw away or keep on hand. A small starter requires less flour and water to feed it, thus resulting in less discard.

For example, I typically maintain my starter with 5 grams of starter, 30 grams of flour, and 30 grams of water. When the starter doubles in size, I discard all but 5 grams and repeat with the same refreshment of flour and water.

If you need more starter for a recipe, build it up by discarding less and feeding it more flour and water.

In short, to reduce sourdough discard, maintain a small sourdough starter.

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How Do You Store Sourdough Discard?

Store sourdough discard in the refrigerator in a sealed container, like a reusable deli container or a Mason jar.

Refrigeration slows down fermentation to a halt and the discard will not rise anymore. The discard has not been fed and thus will not continue to rise.

Additionally, you can store discard in the freezer in a freezer-safe container or ziplock bag. However, I generally don’t recommend freezing discard, unless you need a large amount of it to use for multiple recipes in the future.

I do not store discard at room temperature as it degrades quickly.

How Long Can You Store Sourdough Discard?

You can store sourdough discard in the refrigerator for up to two weeks. However, I recommend using it within the first week of storage.

Over time, the discard becomes extremely acidic and lends a very sour and unpleasant flavor to baked goods or recipes where applied.

It’s possible that a thin layer of brown or black liquid develops on top of the discard while it is stored. This layer of liquid is called “hooch” and is safe to stir into the starter or pour out. Hooch is simply a liquid byproduct (mostly alcohol) of fermentation and is completely normal.

While you can store sourdough discard for longer than two weeks, I toss it after that time to avoid the unpleasant sour flavor. If there is ever mold growing on your discard or it smells bad, throw it away immediately and do not consume.

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What Can You Make with Sourdough Discard?

I have many sourdough discard recipes and use discard in a plethora of savory and sweet applications like cakes, cookies, and muffins.

Since discard does not have the leavening power of sourdough starter, I typically use it in conjunction with other mechanical leavening agents like baking soda and baking powder.

Some of my favorite sourdough discard recipes include:

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What Does Sourdough Discard Taste Like?

In baked goods, sourdough discard is similar to using buttermilk, sour cream, kefir, or yogurt in a recipe. For example, in my Sourdough Biscuits with Cheddar and Chives, Flaky Sourdough Biscuits, or Sourdough Irish Soda Bread recipes, the discard is used in tandem with buttermilk for tanginess.

Depending on how fresh the discard is, sourdough discard tastes acidic, sour, and tangy. If recent, it may have a yeasty taste or smell to it and still be bubbly.

On the other hand, the older the sourdough discard is, the more acidic it becomes.

Old sourdough discard is runny, slimy, and may smell like alcohol due to the fermentation byproducts and the starter being hungry.

Hence, why I recommend using discard in a week so the flavor doesn’t affect recipes.

At 100% hydration, sourdough discard is 50/50 water and flour. Subtract the percentage of hydration and flour from a recipe if modifying a recipe to add discard.

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Can You Make Bread with Sourdough Discard?

Technically, yes, but with some caveats.

It’s always best to use your sourdough starter at its peak for the best leavening performance. This is when the starter is at its peak or within a few hours after. Slowly, the performance degrades as the starter ferments longer and runs out of food.

However, sometimes you may forget to feed your starter, not have enough, or remember you have some discard that’s about to expire in the refrigerator.

If the discard is less than two days old and refrigerated, you can likely use it instead of sourdough starter in a recipe. The leavening might take longer, and the loaf may taste sour.

For older discard, build a levain (an offshoot of your starter), and use the entire levain in the recipe in place of the starter. That will give you a sense of the leavening power of the discard without compromising your bread. Essentially, build another starter using the discard so you can gauge its capabilities.

I find sourdough discard is more forgiving in loaf bread recipes like Sourdough Sandwich Bread than an artisan-style country loaf like My Everyday Sourdough Bread Recipe.

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Can You Feed Discard to Make a Starter?

Generally, yes. Sourdough discard is a hungry sourdough starter that hasn’t been refreshed.

You can build a new sourdough starter using sourdough discard and feeding it as you typically would for a few days. Once functioning and consistently rising and falling, you can use it in recipes as a new sourdough starter.

However, if the new starter fails to rise or double in size after a few days, it likely is not strong enough to leaven bread.

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Can You Compost Sourdough Discard?

Yes, you can compost sourdough discard or sourdough starter!

Do not pour sourdough starter or discard it down the drain, as it can clog your pipes when it dries.

Chickens will also gladly consume discard as a probiotic snack. Dry it first and feed it like a grain.