Sourdough Discard Calculator
Turn leftover sourdough starter discard into something useful — see the flour and water it stands in for and how many pancakes, waffles or crackers it makes.
How it works
Discard (100% hydration) = ½ flour + ½ water by weight · Batches = discard ÷ discard-per-batch · Servings = batches × per-batch yield
Every time you feed a sourdough starter you throw away part of it, and that "discard" is not waste — it is simply flour and water (in equal weights, since most starters are kept at 100% hydration) with a pleasant tang and no leavening power left. That makes it perfect for quick recipes raised by baking soda or eggs: pancakes, waffles, crackers, muffins and quick breads. Knowing the flour-and-water equivalent lets you fold discard into almost any batter, adjusting the recipe's own flour and liquid down to compensate.
Worked example
You have 200 g of discard. Because it is 100% hydration, that is 100 g flour and 100 g water. A pancake batch uses about 227 g of discard for 8 pancakes, so 200 ÷ 227 = 0.88 of a batch — roughly 7 pancakes.
Frequently asked questions
Does sourdough discard still leaven a recipe?
Not reliably. Discard is usually unfed and past its rising peak, so it adds tang and tender texture but little lift. Discard recipes lean on baking soda, baking powder or beaten eggs for rise. If you want the discard to leaven, you would need to feed it and let it become active first — at which point it is no longer discard.
How do I substitute discard into a normal recipe?
Treat discard as equal parts flour and water by weight. To add 100 g of discard, cut 50 g of flour and 50 g of liquid from the recipe to keep the balance. Because discard is acidic, a pinch of baking soda helps neutralise the tang and boosts browning.
How long does discard keep?
Refrigerated in a sealed jar, discard keeps about a week and you can keep topping up the same jar between feedings. For longer storage, freeze it in portions or dry it. Discard that smells sharply of acetone or shows any fuzzy mould should be thrown out.
Related calculators
This calculator is for educational purposes. Double-check important results before acting on them.