Sourdough Starter Calculator

How Sourdough Starter Feeding Works

A sourdough starter is a living culture of wild yeast and beneficial bacteria maintained through regular feedings of flour and water. When you feed your starter, you discard a portion and add fresh flour and water in a specific ratio. The feeding ratio determines how much food the microorganisms receive relative to the existing culture. A higher ratio like 1:5:5 gives the starter more food, resulting in a slower, more predictable rise that develops more complex flavors. A lower ratio like 1:1:1 provides less food, producing a faster rise ideal for daily maintenance or quick turnarounds.

The key to a healthy starter is consistency. Feed at roughly the same time each day, use the same flour type, and keep the temperature relatively stable. A well-maintained starter should roughly double in volume within the expected time frame for your feeding ratio and room temperature. When your starter consistently doubles and has a pleasant tangy aroma, it is ready to leaven bread.

Choosing the Right Feeding Ratio

The 1:1:1 ratio is the most common for daily maintenance. Equal parts starter, flour, and water by weight keeps the culture active and ready to bake within 4 to 8 hours depending on temperature. This ratio works well for bakers who bake frequently and want their starter ready the same day. The 1:2:2 ratio is a good all-purpose choice that gives slightly more food, extending the time to peak and producing a milder flavor. Many experienced bakers prefer this ratio for its balance of convenience and flavor development.

The 1:3:3 and 1:5:5 ratios are ideal for warmer environments or when you want to slow down fermentation. In summer months when kitchen temperatures exceed 75 degrees Fahrenheit, a higher ratio prevents your starter from peaking too quickly and becoming over-fermented. The 1:5:5 ratio is also useful before an overnight rest, giving the starter enough food to remain active until morning. Whole wheat and rye flours ferment faster than all-purpose flour due to higher enzyme activity, so consider using a higher ratio when feeding with these flour types.

Temperature and Timing for Sourdough Starter

Temperature is the single most important factor affecting fermentation speed. At 65 degrees Fahrenheit, a 1:1:1 feeding takes approximately 12 hours to peak. At 80 degrees, the same feeding peaks in roughly 4 hours. This is why professional bakers control dough temperature precisely. For home bakers, knowing your kitchen temperature helps you plan feeding times around your baking schedule. If your kitchen runs cool, place the starter near a warm appliance or use a proofing box. If it runs warm, use cold water for feedings or store the starter in a cooler spot.

Planning backwards from your desired bake time is the most reliable approach. If you want to mix dough at 9 AM and your kitchen is 70 degrees Fahrenheit, feed your starter the night before around 1 AM for a 1:1:1 ratio, or at 9 PM the previous evening for a 1:2:2 ratio. This calculator handles the math automatically when you enter your bake date and time. The multi-feed planner is especially useful when you need a large amount of starter but only have a small amount on hand, showing you exactly how many feedings it takes to build up to your target quantity.

Common Sourdough Starter Problems

If your starter is not rising, the most likely causes are low temperature, weak culture, or insufficient feeding frequency. Try moving it to a warmer location and feeding twice daily with whole wheat or rye flour to boost microbial activity. If it smells strongly of acetone or nail polish remover, it has been underfed and needs more frequent feedings with a higher ratio. A healthy starter should smell pleasantly sour, like yogurt or mild vinegar, with some fruity or yeasty notes. Hooch, the dark liquid that forms on top, is harmless alcohol produced by hungry yeast. Simply pour it off or stir it back in and feed your starter.