What this Sourdough Starter Feeding Calculator does
The Sourdough Starter Feeding Calculator estimates the combined weight of flour and water to add to a portion of starter you plan to keep. It uses a feeding ratio stated in parts by weight. For example, a 1:1:1 ratio means one part starter, one part flour, and one part water. If you keep 50 grams of starter at that ratio, the calculation gives 50 grams of flour and 50 grams of water, or 100 grams of total feed.
The result is a planning aid for weighing ingredients. It does not determine when a starter is ready to bake, predict how quickly it will rise, or recommend a feeding schedule. Those outcomes depend on conditions such as temperature, flour, hydration, and starter activity. Use a scale for the weights and follow the method for your bread recipe.
How to use the Sourdough Starter Feeding Calculator
Enter the weight of the starter you are keeping, then set the flour and water parts in your desired ratio. The calculator multiplies the kept starter weight by each ratio amount and adds the two ingredient weights. Its output is the total weight of flour and water, not the final starter weight.
- Weigh the starter you intend to retain after discarding or transferring the excess.
- Enter that amount in grams in “Starter to keep.” The available range is 1 to 500 grams.
- Choose the flour amount per one part starter. The range is 1 to 10 parts.
- Choose the water amount per one part starter. The range is 0.5 to 10 parts.
- Read “Total Feed” to see the combined flour and water weight.
For instance, if you keep 40 grams of starter and use 2 parts flour and 1 part water, the tool calculates 80 grams of flour plus 40 grams of water. The total feed is 120 grams. Weigh the two ingredients separately according to the ratio.
How the Sourdough Starter Feeding Calculator formula works
The formula is starter weight × flour ratio + starter weight × water ratio. The ratios are amounts per one part of starter. Since all three quantities are expressed by weight, each multiplication produces grams when the starter input is in grams.
Using the default values, 50 grams of starter, 1 flour part, and 1 water part produce this calculation: (50 × 1) + (50 × 1) = 100 grams of feed. That consists of 50 grams of flour and 50 grams of water. The starter itself is not included in the displayed total. If you want the approximate combined weight after feeding, add the kept starter to the feed. In this example, that is 50 + 100 = 150 grams.
The model treats the flour and water amounts independently. A 1:2:1 feed means one part starter, two parts flour, and one part water. A 1:1:2 feed means one part starter, one part flour, and two parts water. This makes it possible to represent different ratios without a built-in menu of named feeding styles.
Use cases for the Sourdough Starter Feeding Calculator
Home bakers can use the estimate when refreshing a starter before mixing dough, maintaining a smaller jar, or scaling a feed to a particular amount on hand. It can also help when a recipe states a ratio and you want to turn that ratio into scale measurements.
- Routine maintenance: Calculate a modest feed around the amount of starter you choose to retain.
- Preparing for a recipe: Estimate the feed ingredients, then allow the starter to ferment according to your usual process.
- Adjusting a ratio: Compare flour-heavy or water-heavy feeds by changing the parts per one part starter.
- Reducing leftovers: Start with a smaller retained amount when your baking plan calls for less starter, while accounting for the amount your recipe needs.
These examples describe uses for the arithmetic. The calculator does not know how much ripe starter a specific recipe requires, so check the recipe before deciding how much to retain and feed.
Other factors to consider when calculating a feed
Ratios are commonly expressed by weight, but a spoon or cup measurement can vary with how flour is packed. A kitchen scale gives measurements that correspond to the model. Also check whether a recipe’s ratio order is starter, flour, then water. Conventions can vary, and the labels here make the intended order explicit.
The calculator assumes you have already selected the quantity of starter to keep. It does not subtract discard, track the amount in a jar, or account for ingredients stuck to a bowl or utensil. If your scale rounds to whole grams, small calculated differences may not be practical to measure precisely.
Finally, feeding quantity is only one part of starter care. The calculator cannot assess smell, bubbles, rise, maturity, contamination, or fermentation timing. Use your established baking method and sensory checks to make those decisions.
Frequently asked questions
Does the total feed include the starter?
No. The result adds the flour weight and water weight only. Add the retained starter weight to the result if you want the approximate total mixture weight after feeding.
What does a 1:1:1 feeding ratio mean?
It means equal weights of starter, flour, and water. With 50 grams of starter, that ratio calls for 50 grams of flour and 50 grams of water, for a 100-gram feed.
Can I use a different flour-to-water ratio?
Yes. Enter the number of flour parts and water parts for each one part of retained starter. The tool calculates those ingredient weights separately and reports their sum.
Can this calculator tell me when the starter is ready?
No. It calculates feed weight from the numbers you enter. Readiness and fermentation time depend on conditions and starter behavior, so use the signs and timing in your chosen baking method.
Why does the tool use grams?
Grams make it straightforward to apply a ratio by weight. If your recipe uses another unit, convert consistently before entering values, or weigh ingredients in grams to avoid volume-measure variation.