Feeding Ratios, Ripening Checks and Dough Temperature
Hydration is the arithmetic of a sourdough recipe; the starter is the part that is alive,
and living things keep their own schedule. That is why two bakers can follow the same
formula and get dough that proofs in four hours and dough that proofs in nine. The
published extension and test-kitchen guidance below covers the two variables you actually
control — how much food you give the starter, and how warm you keep the dough.
Starter feeding and storage, from Clemson Extension and the King Arthur Baking test
kitchen. Ratios are by weight, not volume.
| Practice | Published guidance | What it means for your schedule |
| Maintenance ratio | A minimum of 1:1:1 — equal parts starter, flour and water by weight, discarding starter at each feed | One part starter carried over, one part fresh flour, one part water. |
| A worked 1:1:1 feed | 50 g starter + 50 g flour + 50 g water = 150 g of starter, about ⅔ cup | King Arthur calls 150 g an ideal amount to keep on hand; scale all three numbers together to keep more. |
| Kept at room temperature | Feed it daily | The organisms in a starter thrive at room temperature, so this is the option for baking several times a week. |
| Kept in the refrigerator | Feed it about once a week, then give it a few room-temperature feedings before baking | Cold storage slows the culture; the extra feedings are what wake it back up. |
| Readiness — rise | It should rise to double its size within 4 to 6 hours after feeding | Clemson Extension's first test. No rise means keep feeding on the 12-hour routine. |
| Readiness — float test | A small spoonful placed in a bowl of water floats when the starter is ready | Clemson Extension's second test, and the quickest one to run on the day. |
| Beyond the minimum | Higher flour-to-starter ratios extend the time between feedings | Use them when you want to feed tonight and bake tomorrow rather than twice a day. |
Dough temperature, and what it does to proofing time
Once the dough is mixed, temperature is the dial. Yeast activity rises with warmth, so a
dough that proofs in a warm kitchen can finish in half the time of the same dough on a cold
counter, and the failure mode at the fast end is over-proofing — the dough puffs,
then collapses, and no amount of baking brings the structure back. King Arthur's baking
ambassador Martin Philip puts the working band for bread dough at 72 °F to 78 °F,
described as warm enough to encourage yeast activity without letting the dough move so fast
that it over-proofs or fails to develop flavour.
With the dough in that band, proofing is judged by the dough rather than the clock. Bread
typically doubles, or nearly doubles, in size as it proofs. For a shaped loaf in a tin the
published test is height: look for the dough to rise about an inch above the lip of the pan
and measure it rather than guessing. For a free-form loaf the test is the poke —
lightly flour a finger, press the dough down about an inch, and read the indentation. If
the indent stays, the loaf is ready to bake; if it springs back out, it needs more time.
Where the starter goes in the hydration arithmetic
A starter is not a free ingredient. At 100 per cent hydration it is half flour and half
water by weight, so it counts toward both sides of the ratio. The table works the same
dough three ways: 500 g of total flour, 100 g of starter, and three target hydrations. In
every row the flour you add is 450 g, because 50 g of the flour is already inside the
starter.
One dough, three targets: 500 g total flour including 100 g of 100 per cent hydration
starter (50 g flour + 50 g water).
| Target hydration | Total water | Water still to add | Flour still to add |
| 65% — stiff, for sandwich loaves | 325 g | 275 g | 450 g |
| 70% — a middle ground | 350 g | 300 g | 450 g |
| 75% — open-crumb country loaf | 375 g | 325 g | 450 g |
| 80% — high hydration, harder to handle | 400 g | 350 g | 450 g |
Read the third column as the number you put on the scale and the second as the number you
are aiming at. If you change the starter weight, both the flour and the water you add move
in opposite directions, which is exactly the correction the calculator above automates. For
the leavening conversions that sit alongside this one, see the
yeast
converter and the
bread proofing
calculator, and for the bake itself the
oven
temperature converter covers the gas-mark and convection adjustments.
Sources: Clemson University Home & Garden Information Center, “How to Make, Feed, and Bake With a Sourdough Starter”;
King Arthur Baking, “Feeding and Maintaining Your Sourdough Starter”;
King Arthur Baking, “What is proofing bread? And how do I get it right?”.