Sourdough Starter & Feeding Calculator
Calculate the exact amounts for feeding your sourdough starter at any hydration level, and find out how much starter to maintain for your baking schedule.
As an Amazon Associate and CJ Affiliate publisher we earn from qualifying purchases. Prices and availability may vary.
Sourdough Starter Guide
What should I know about Understanding Feeding Ratios?
The feeding ratio (starter:flour:water) controls fermentation speed. A 1:1:1 ratio (equal parts) peaks in 4-6 hours at room temperature — suitable for same-day baking. A 1:2:2 ratio takes 6-8 hours. A 1:5:5 ratio is used for an overnight counter fermentation or a cold-retarded 12-hour proof. A 1:10:10 ratio produces very gradual fermentation over 24+ hours. Choose the ratio based on your baking schedule — you want to use the starter at peak activity (domed top, full of bubbles, just before it starts to fall back down, since this is when the wild yeast and bacteria are at their most active and give the best rise in a subsequent bake.
What do I need to know about Starter Hydration?
Starter hydration is expressed as a percentage of water to flour by weight. 100% hydration (equal weight flour and water) produces a thick batter — most common for beginners, easy to assess activity by volume. 125% hydration: slightly more liquid, more active, slight tang. 75% hydration: stiffer, longer fermentation, milder flavour — used for Italian lievito madre. Higher hydration starters ferment more quickly and show more activity. Lower hydration starters are more stable for long storage and travel, since the stiffer consistency is less prone to separating or developing hooch between feeds.
What's the key thing to understand about Reading Your Starter?
Signs of a healthy, active starter at peak: doubled or more in size (mark the container with tape before feeding). Domed top — not yet fallen back down. Interior is full of bubbles, webby, honeycomb structure. Smells pleasantly sour and yeasty — like yogurt or mild beer. Floats when a small amount is dropped into water (the float test — not infallible but indicative of active fermentation). Signs of an unhealthy starter: a liquid layer on top, known as hooch, meaning the starter has run out of food — either stir it back in for a milder flavour, or pour it off and feed immediately for a fresher-tasting starter.
What should I know about Discard Uses?
Sourdough discard is unfed starter that would otherwise be thrown away — it has weaker leavening power than active starter but retains all the flavour. Discard uses: sourdough pancakes (tangy and light), waffles, flatbreads, pizza dough, crackers, banana bread. Discard can be stored in the fridge for up to a week and added to recipes for flavour without leavening. Adding discard to yeasted recipes gives sourdough flavour with reliable rise from commercial yeast. Never waste discard — it develops genuine sourdough flavour even without leavening power, making it perfect for pancakes, crackers, and flatbreads.