Sourdough Starter & Feeding Calculator

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.

What should I know about Starter Maintenance Schedules (Fridge vs Counter)?

How often a sourdough starter needs feeding depends almost entirely on whether it's kept at room temperature or refrigerated, and choosing the wrong schedule for your baking frequency is one of the most common reasons starters become either weak or wastefully high-maintenance. A starter kept on the counter at room temperature is active and hungry, typically needing feeding once or even twice a day, since it will consume its available food and start to weaken (or develop very strong, vinegary off-notes) within 12-24 hours — this schedule suits people baking bread multiple times a week. A starter kept in the fridge slows down dramatically, needing feeding only about once a week, making it far better suited to occasional bakers, since the cold suppresses yeast and bacterial activity without killing it. Switching a starter from fridge to counter storage (for example, the few days before a baking session) should be done gradually where possible — feeding it once while still cool, then letting it warm and become fully active with one or two further feeds before using it in a dough — rather than expecting a fridge-cold starter to perform at its peak immediately after waking it up.

What do I need to know about Reviving a Neglected or Dead-Looking Starter?

A starter that's been neglected in the fridge for weeks or months, showing a layer of dark liquid ('hooch') on top, a strong alcoholic or acetone-like smell, or little to no rise after feeding, is very often still alive and recoverable rather than truly dead, since dormant wild yeast and lactic acid bacteria can survive long dormant periods. The first step is to pour off or stir in the hooch (a sign the starter is hungry and has been fermenting past its food supply, not necessarily a sign of spoilage) and discard all but a small amount (roughly a tablespoon) of the starter, then feed it with fresh flour and water at a consistent ratio. Expect several feeding cycles, often over 2-5 days, feeding once or twice daily and discarding most of the starter each time, before it returns to reliably doubling in size within a predictable window, since it takes time for the yeast and bacteria population to rebuild after a long dormant period. Only if a starter shows clear signs of actual spoilage — pink, orange, or fuzzy mould growth, rather than the harmless grey or clear hooch liquid — should it be discarded entirely and a new one started, since mould in these colours (unlike the beige/tan colour of simple surface drying) indicates genuine contamination rather than normal dormancy.

Worked Example: Feeding at a 1:5:5 Ratio

Feeding ratios describe starter : flour : water by weight. A maintenance ratio of 1:1:1 (keeping, say, 50g starter and adding 50g flour and 50g water) ferments relatively quickly, often peaking in 4-8 hours at room temperature, and suits bakers who feed daily. A larger ratio such as 1:5:5 (50g starter with 250g flour and 250g water added) dilutes the existing yeast and bacteria much further, so it takes noticeably longer to peak, often 8-12+ hours, and produces a milder-tasting, less acidic starter because the lower proportion of already-fermented starter slows the rate at which acidity builds. Bakers who feed only every few days, or who want a less sour loaf, often favour the larger-ratio approach for this reason, while daily-fed starters kept at 1:1:1 tend to be more reliably and quickly ready to use.

Signs Your Starter Is Ready to Bake With

The float test (dropping a small spoonful of starter into water to see if it floats) is a popular quick check, but it isn't fully reliable on its own, since a starter can float due to trapped gas even when it isn't at its strongest fermenting point, or sink despite being perfectly usable if it's a particularly dense or stiff starter. More reliable combined signs are: a roughly doubled or more volume compared with right after feeding, a domed rather than flat or sunken surface, visible bubbles throughout rather than just at the top, and a pleasant tangy, slightly yeasty smell rather than a sharp acetone-like or alcoholic smell (which suggests the starter has already peaked and started to decline, and is hungry). Using a starter at or just before its peak, rather than well past it, generally gives the most reliable rise in the final dough.

Why Hydration Affects How a Starter Behaves

A thicker, lower-hydration starter (closer to 50-75% water relative to flour) tends to rise more slowly but holds its structure longer past peak, giving a slightly wider window to use it before it over-ferments, while a thinner, higher-hydration starter (100%+ water) typically ferments faster and more vigorously but can collapse and become overly acidic sooner after peaking if not used or re-fed promptly. Neither hydration level is objectively better; the choice mostly comes down to a baker's feeding schedule and how predictable they need peak timing to be, with thicker starters generally suiting less frequent or less precisely timed feeding routines.

Why Flour Type Changes Starter Behaviour

Whole grain flours such as wholemeal or rye contain more of the natural yeasts, bacteria and nutrients found in the outer bran and germ of the grain than refined white flour does, which generally makes a starter ferment faster and more vigorously when fed partly or fully with whole grain flour, though often at the cost of a looser, less structured rise compared with one fed purely on strong white flour. Many bakers feed a blend, such as mostly white flour with a smaller proportion of wholemeal or rye, to balance the faster, more reliable fermentation whole grains encourage against the more predictable structure a higher proportion of white flour tends to give the finished starter and dough.