Guide · sourdough

What to do with sourdough discard

Why you discard, what discard actually is, how to store it, and the best ways to use it instead of throwing it away — plus how to discard less in the first place.

Every time you feed a starter you discard most of it first — and new bakers hate throwing it away. The good news: discard is perfectly usable, and with the right feeding approach you can generate far less of it. Here's what discard is, why it exists, how to keep it, and what to do with it.

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The mature starter you’ll feed. Discard the rest.
1 : :
If set, we’ll show how much to discard.
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Feeding Result
Add flour250g
Add water250g
Resulting starter550g
Ratio1:5:5
Peak~8–14 hours
Best forOvernight levain; milder flavour
Peak time is an estimate — it depends on your starter’s health and kitchen temperature. Watch for roughly double in size and a domed top; trust the rise, not the clock.
Next Once this levain peaks and you mix it into dough, its own flour and water change your true hydration. Work out levain-aware hydration →
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What discard is, and why you discard

Discard is simply the portion of mature starter you remove before feeding. You discard for two reasons: to keep the culture from becoming too acidic over time, and to keep your feeding ratio accurate — if you fed all of an ever-growing starter, you'd need ever-growing amounts of flour and water, and the ratio would drift.

It's not waste — it's just unfedDiscard isn't spoiled or bad. It's mature starter that simply hasn't been fed again. Unfed, it's more acidic and has less leavening power, which is exactly why it's great in recipes that don't rely on it to rise.

How to store discard

Keep a separate jar in the fridge and add each day's discard to it. Stored cold, it keeps for about a week or two — give it a stir if liquid (hooch) separates on top; that's harmless and just a sign it's hungry. If it ever grows fuzzy mould or smells genuinely foul rather than sour, throw it out.

What to use it for

How to discard less in the first place

The honest fix for too much discard isn't more discard recipes — it's keeping a smaller starter. If you only keep what you need, you discard almost nothing. Two approaches:

The calculator's “I need this much levain” mode does exactly this — enter the amount your recipe calls for and it tells you the small seed to begin with, so you generate the least discard possible.

MC
The MeasureChef team
Builds calculators and reference tools for bakers and makers. Storage and food-safety guidance follows standard sourdough references.

Sources and method: see our methodology and references.

What is sourdough discard?
The portion of mature starter you remove before feeding. It's unfed starter — more acidic and with less leavening power, but perfectly usable in recipes that don't rely on it to rise.
Why do you discard sourdough starter?
To stop the culture becoming too acidic and to keep your feeding ratio accurate. Feeding an ever-growing starter would need ever-growing amounts of flour and water.
How long does sourdough discard keep?
About one to two weeks in the fridge in a separate jar. Stir in any liquid that separates on top. Discard it only if it grows mould or smells genuinely foul.
How do I avoid having so much discard?
Keep a small maintenance starter — 20–50 g is plenty — and build up to a recipe's amount only when you bake. Working backwards from the levain you need minimises leftover.

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