A sourdough feeding ratio is written as starter:flour:water by weight. A 1:2:2 feed gives every 10 grams of retained starter 20 grams of flour and 20 grams of water. Higher flour-and-water ratios usually take longer to peak, which lets you match a healthy starter to your baking schedule.
Read the three numbers correctly
The first number is the amount of existing starter you keep, sometimes called seed starter. The second is new flour, and the third is new water. All three are compared by weight, not by cups. A scale matters because a cup of bubbly starter, a cup of compacted flour, and a cup of water do not weigh the same.
At 1:1:1, 25 grams of starter receives 25 grams of flour and 25 grams of water, producing 75 grams total. At 1:2:2, the same 25 grams receives 50 grams each of flour and water, producing 125 grams. At 1:4:4, it receives 100 grams each, producing 225 grams.
These examples have equal flour and water in the feed, so the new food is at 100% hydration. If the retained starter is also 100% hydration, the fed starter remains at 100% hydration. A stiff starter might use unequal flour and water, such as 1:2:1. That is a valid ratio notation, but its timing and behavior should not be compared directly with a liquid 1:2:2 starter.
Feeding ratio comparison
| Ratio | Example | General timing effect | Useful when |
|---|---|---|---|
| 1:1:1 | 30g + 30g + 30g | Usually peaks sooner | You need active starter later the same day |
| 1:2:2 | 20g + 40g + 40g | Moderate extension | You want more food and a wider schedule |
| 1:4:4 | 10g + 40g + 40g | Usually peaks later | You are planning an overnight build |
| 1:5:5+ | 10g + 50g + 50g | Longer, condition-dependent cycle | Your established starter and temperature support it |
The table describes direction, not a universal clock. King Arthur Baking’s controlled comparison at about 78°F found a healthy mature 1:1:1 starter peaking around four to six hours, while its 1:2:2 and 1:4:4 examples peaked later. The author explicitly notes that starter health and kitchen temperature can shift those times. Use the ratios as scheduling levers and learn the actual curve of your own culture.
Why a larger feed usually takes longer
When you keep the seed amount constant but add more fresh flour and water, the existing microbial population has more food to process before the starter reaches maximum expansion and begins to fall. The mixture is also more diluted at the beginning. That generally lengthens the interval between feeding and peak.
Temperature can outweigh the ratio. A warm starter ferments faster than the same feed in a cool room. Flour choice, water temperature, starter maturity, acidity, consistency, and feeding history also matter. Changing several variables at once makes it difficult to learn why the peak moved.
For a repeatable experiment, use the same flour, water, container, seed starter, and location for three feeds. Mark the starting height with a band, record the time, and note when the starter reaches its highest point. Then change only the ratio and repeat. Your notes become a much better scheduling guide than someone else’s exact hour count.
Choose a ratio from your target time
You want to mix dough this afternoon
If your established starter reliably peaks within your available window at 1:1:1, use that known feed. King Arthur describes ripe starter as bubbly, expanded, and roughly doubled, often around six to eight hours after feeding in its maintenance example. Watch the starter rather than assuming a fixed alarm applies to every kitchen.
You want starter ready the next morning
A larger feed such as 1:4:4 may extend the cycle enough for an overnight build. Test this before an important bake. If your kitchen is very warm, the starter may peak and fall overnight; in a cool room, it may still be rising. Adjust the ratio, seed temperature, or feeding time on the next trial—not all three at once.
You keep starter in the refrigerator
Refrigeration is a maintenance choice, not a fixed feeding ratio. King Arthur recommends regular refrigerator maintenance and one or more room-temperature feeds before baking, depending on activity. Use the instructions for your established starter method. A neglected culture may need repeated feeds before it rises predictably.
You need an exact amount for a recipe
Work backward from the required ripe starter plus a small amount to retain. If a recipe needs 180 grams and you want 20 grams left, target 200 grams. A 1:2:2 feed contains five ratio parts, so each part is 40 grams: 40 grams starter, 80 grams flour, and 80 grams water. Our starter feeding calculator performs this calculation and shows expected discard.
Hydration and feeding ratio are different
Feeding ratio compares seed, flour, and water. Hydration compares total water with total flour. A 1:1:1 starter made from a 100%-hydration seed remains at 100% hydration because the new flour and water are equal. But if the seed is stiff, its existing flour and water must be included to find the final hydration accurately.
This distinction matters when a bread formula includes starter. A recipe with 100 grams of 100%-hydration starter receives 50 grams of flour and 50 grams of water from that starter. Use the sourdough hydration calculator to include those contributions instead of treating the entire starter weight as extra water.
Recognize peak rather than chasing a number
Mark the starter level immediately after feeding. As it ferments, look for distributed bubbles, increasing volume, and a top that changes from domed to level as the peak approaches. After peak, streaks above the starter and a falling surface show that it has begun to recede.
“Double in volume” is a practical marker, not a law of microbiology. Container width, flour strength, hydration, and gas retention affect visible rise. A very liquid starter may be active without holding a tall structure. Learn a combination of rise, aroma, bubbles, elapsed time, and repeatability.
The float test is not a reliable replacement for this broader assessment. Whether a spoonful floats depends partly on trapped gas and handling. A starter can be active yet sink after stirring, or float without being at the ideal stage for a particular formula.
Troubleshoot feeding problems
It peaks too early
Feed at a higher ratio, choose a cooler stable location, or feed later. Change one variable and record the result. Do not place the culture in an unsafe temperature environment merely to force a convenient schedule.
It barely rises after a large feed
A weak or immature starter may be excessively diluted by a very high ratio. Return to the established maintenance method and repeat regular feeds. Check that the water was not excessively hot, the flour is appropriate, and the room is not unusually cold.
It smells sharp and falls long before feeding
The culture may be spending too long past peak. Feed sooner or use a higher ratio that matches the interval. An alcoholic or acidic aroma can occur in a hungry starter, but visible mold or pink, orange, or otherwise unusual discoloration is a discard signal in university extension guidance.
The amounts create too much discard
Ratios scale. Maintaining 10 grams at 1:2:2 produces only 50 grams total; maintaining 50 grams produces 250 grams. Keep a small mother starter, then build the amount required before baking. Do not reduce the food relative to the seed just to make the jar smaller.
Food-safety basics
Use clean equipment and ingredients intended for food preparation. Raw flour can contain harmful microorganisms, so do not eat raw starter or dough. Baking supplies the kill step. Discard a starter with visible mold or suspicious colored growth rather than scraping the surface and continuing. When health risk is elevated, follow guidance from a qualified medical or food-safety professional.