How to feed and maintain a sourdough starter
For an established flour-and-water starter, weigh the portion you will keep, then add fresh flour and water. Decide whether you are maintaining the culture or building enough for a bake. The planner below makes that distinction explicit; it calculates quantities, not a guaranteed feeding time.
Small-batch starter feeding planner
Your next feed
- Starter to keep for this feed
- 20.0 g
- Fresh flour
- 20.0 g
- Fresh water
- 20.0 g
- Total levain
- 60.0 g
- Not used in this feed
- 180.0 g
Seed : flour : water: 1 : 1.000 : 1.000
Target hydration: 100.0%
This is the jar amount left after taking the seed. It is not automatically a safe discard ingredient; consider the culture’s age and condition before using it.
Mix these quantities in a suitable container and mark the starting level. Observe the rise; this calculation does not assess the culture’s health or predict when it will peak.
Weights are displayed to 0.1 g. Small differences in their rounded sum are normal. Hydration is a formula ratio, not a promise about dough handling or fermentation time.
Read a feeding ratio by weight
Here, 1:2:2 means one part retained starter, two parts fresh flour and two parts fresh water. With 20 g starter, that is 40 g flour and 40 g water, producing 100 g fed starter. The old starter is a separate ingredient; do not count its full weight as flour or as water.
At 100% hydration, a 20 g seed contains 10 g flour and 10 g water. Adding 40 g of each gives 50 g total flour and 50 g total water. For a stiff or liquid seed, open the hydration settings. The planner includes the seed’s existing water when solving the new feed, so the actual fresh-water ratio may differ from the fresh-flour ratio.
Keep a maintenance jar small; build a bake separately
Choose how much starter to retain before adding flour. In the default example, a jar containing 200 g supplies 20 g seed. A 1:1:1 feed makes a new 60 g batch; the other 180 g is simply not used in that feed. It is not part of the new starter total. Feeding all 200 g at the same ratio would make 600 g instead.
For a bake, work backward from the ripe starter required by the bread recipe and add a separate reserve for the next feed. The linked levain builder calculates that recipe batch. A small maintenance feed and a bread-sized levain serve different needs; neither requires keeping a large jar between bakes.
Choose a counter or refrigerator routine
King Arthur’s published maintenance method starts with daily counter feeding or weekly refrigerator feeding. Treat that as a method to follow and adjust, not a universal timer for every culture. A warmer kitchen can change the pace. Before baking with refrigerated starter, refresh it at room temperature and check its response.
Record the feed time, room temperature, retained amount, added flour and water, and starting level. These notes help you compare the same culture under the same conditions. Do not use the clock alone to decide that a quiet starter is ready or spoiled.
Changing the ratio changes the feed, not just the yield
More fresh flour per gram of seed changes how much food the culture receives. King Arthur’s ratio trials show why the same starter can peak at different times after different feeds. Their times describe their test conditions, not your kitchen. This planner therefore reports the actual ratio and mass without inventing a peak-time forecast.
Start from a routine you already understand. When testing a change, record it and compare the observed rise. If you change retained seed, flour, hydration and temperature together, it becomes harder to tell which change mattered.
Anstellgut, ripe starter and the bread recipe
German recipes often call the retained culture Anstellgut and the recipe build Sauerteig. Read the recipe to see which portion it expects. Plötzblog provides a German reference for refreshing Anstellgut and judging its rise. Its routine and King Arthur’s routine are separate methods; do not combine their quantities and timings into one instruction.
Before transferring a batch into dough, weigh the recipe portion and keep the maintenance reserve separate. The bread hydration calculator counts the flour and water inside the starter you actually add. A reserve left in the jar is not an ingredient in the dough.
What the calculator cannot fix
A new flour-and-water mixture needs a starter-creation method, not merely this feeding calculation. Early activity is not proof that it is ready to raise bread. Use a documented method and consistent activity to judge development; the linked starter guide explains that distinction.
Visible mold, pink or orange discoloration, or a putrid smell are reasons to discard the culture and start again, following King Arthur’s troubleshooting guidance. A feed calculation cannot make a contaminated culture safe. Do not turn every unused portion into a discard recipe automatically.
Do I have to throw away all the unused starter?
The result only measures what you did not retain for this feed. It does not prescribe disposal or certify it for food use. A healthy established culture may have other uses; a new or spoiled culture needs different handling.
Why are flour and water unequal in my result?
Your seed already contains flour and water. When seed hydration and final hydration differ, equal additions may not reach your target. The planner adjusts fresh water to account for the seed.
Why is there no exact next-feeding time?
Quantity and hydration determine the formula, not the culture’s strength, flour or room temperature. Watch its behaviour and follow a suitable maintenance method rather than treating a computed time as a guarantee.
Baking references
Sources checked 7 October 2026. King Arthur references are in English; Plötzblog is in German. These are published methods, not trials conducted by BreadHydration.