Sourdough Starter Feeding Calculator

Keeping a Sourdough Starter Healthy Between Feedings

A well-fed sourdough starter stays predictable when the refresh matches the way you bake. The right flour-and-water split keeps the culture active without making it runny or too stiff, and it also makes the starter easier to judge by smell, bubbles, and rise. Use the calculator to land on a feeding amount that keeps the jar lively and ready for the next mix.

Home bakers often keep starter on the counter for frequent baking or in the fridge for longer breaks between loaves. Either approach works better when you know exactly how much flour and water to add, because the refresh can be scaled for a tiny maintenance jar or a larger build for several doughs. That consistency saves flour, reduces guesswork, and makes the starter easier to manage from one feeding to the next.

Introduction: Sourdough Starter Hydration Levels

In sourdough starter feeding, hydration is the ratio of water to flour by weight after the refresh. A 100% hydration starter uses equal weights of flour and water, while a lower percentage makes a firmer paste and a higher percentage creates a looser, more fluid starter. This calculator lets you choose the hydration that matches the starter style you already maintain.

That ratio matters because the starter you keep on hand becomes part of the formula for your next dough. If its hydration drifts, the dough mix changes with it, especially when a recipe expects a particular starter consistency. Feeding to the same hydration each time keeps the starter predictable so you can plan fermentation, timing, and flavor with less recalculation.

Sourdough Starter Hydration Formula

The sourdough starter feeding calculator solves the flour-and-water split from your current weight, target weight, and desired hydration. In MathML, the calculation looks like this:

Formula: F = A / (1 + H / 100), W = A − F

$$F=\frac{A}{1+\frac{H}{100}},W=A-F$$

Here $A$ is the amount of new starter you need to add to reach the target total, $H$ is the hydration percentage, $F$ is the flour portion, and $W$ is the water portion. The formula simply divides the added weight so the final mixture lands at the hydration you selected.

Setting a Sourdough Starter Target Weight

Setting the target weight for a sourdough starter feed is really about deciding how much culture you want ready after the refresh. A baker making one loaf may only need a small maintenance jar, while someone building levain for several doughs may want a much larger batch. Enter the total you want at the end, and the calculator works backward to the flour and water amounts.

When you revive starter from the fridge, you might begin with a larger feed to wake it up, then move back to a smaller routine once it is active again. A steady feeding pattern makes the starter easier to manage, because the same ratio and total weight produce familiar rise behavior from one refresh to the next. That is much easier than guessing by eye when you need a reliable culture for baking day.

Why Regular Sourdough Starter Feedings Matter

Regular sourdough starter feedings keep the culture from running out of food and help prevent the sharp, neglected smell bakers often recognize right away. Fresh flour and water restore the balance of yeast and bacteria, which supports a stronger rise and a more pleasant aroma. The calculator gives you the exact refresh amounts so you can stay on schedule without doing the math by hand.

Consistent feedings also make the starter easier to read. If it rises quickly, slows down, or develops hooch, the issue may be the feed interval, temperature, or flour choice rather than the refresh math itself. Once the feed ratio is set, you can fine-tune the starter by adjusting warmth, flour type, or timing and keep notes on how it behaves after each feeding.

Sourdough Starter Feeding Example Calculation

Pretend you have 50 grams of starter and want 150 grams at 100% hydration for tomorrow's dough. When you enter those numbers, the calculator tells you to add 50 grams of flour and 50 grams of water. If you choose 75% hydration instead, the flour and water split shifts to about 57 grams of flour and 43 grams of water, giving you the same final total with a stiffer mix.

That kind of calculation is useful when you are building enough starter for a levain or increasing your maintenance amount after a bake. Because the calculator handles the ratio every time, you can scale up or down without changing your method, which keeps the starter's behavior familiar and makes it easier to plan overnight timing.

Feeding Comparison Table by Hydration

Use this sourdough starter feeding table to see how a firmer or wetter refresh changes the split between flour and water while the final weight stays the same.

Troubleshooting a Sourdough Starter Feeding Schedule

If a sourdough starter is sluggish, the problem is often not the calculator but the conditions around the feed. Whole grain flour usually brings more activity than white flour, warmer water can speed things up, and a cool kitchen can slow the rise. Use the calculated flour and water amounts first, then adjust the flour blend, temperature, or feeding interval if the starter still looks sleepy.

A starter that smells very sharp or produces hooch may simply need a larger refresh or a shorter gap between feedings. Because this calculator lets you choose the starting and ending weights, you can increase the feed size without changing your hydration target. That gives the culture fresh food while keeping the texture consistent enough to judge whether the issue is hunger, temperature, or just an overripe jar.

Sourdough Starter Feeding Limitations and Assumptions

This sourdough starter feeding calculator assumes the starter you keep is already close to the hydration you enter, because the formula only splits the additional weight between flour and water. If the starter in your jar is much drier or wetter than your target, the result still tells you how to feed forward, but it does not retroactively describe the starter you already have.

The calculator also does not account for room temperature, flour strength, or the starter's age, all of which influence how quickly it rises after a feed. Treat the output as a precise mixing guide, then observe your starter's response and adjust your routine if it peaks too early or too late for your baking schedule.

Sourdough Starter Feeding Conclusion

The Sourdough Starter Feeding Calculator makes routine maintenance easier by turning your current weight, target weight, and desired hydration into clear flour and water amounts. That means less guessing at the counter and a better chance of keeping the starter in the texture you like. Whether you refresh it daily or only before baking, the calculator helps you keep the culture ready.

Use it whenever you want to scale a small jar, rebuild starter after a bake, or change the hydration for a different bread style. With consistent numbers and a repeatable method, your starter becomes much easier to manage, and the feeding step stops feeling like a chore.

How to use this sourdough starter feeding calculator

1. Enter Current Starter Weight (g) — the amount of starter already in the jar.
2. Enter Hydration (%) — the starter consistency you want after feeding.
3. Enter Desired Total Weight (g) — the finished starter weight you want to end up with.
4. Click Calculate, then compare the flour and water results with a second sourdough starter feeding scenario before you mix.