Why Feeding Ratio Matters
The feeding ratio determines how much fresh flour and water you add relative to the amount of existing starter you keep. A 1:1:1 ratio (equal parts starter, flour, and water by weight) doubles the starter volume and ferments quickly, usually peaking in 4 to 6 hours at room temperature. A 1:3:3 ratio dilutes the starter more, slowing fermentation to 8 to 10 hours. A 1:5:5 ratio creates a very slow rise of 12 to 16 hours, ideal for overnight levains or when you cannot tend the starter for a while. Choosing the right ratio lets you time your baking schedule precisely.
Temperature and Peak Time
Ambient temperature is the other major factor controlling fermentation speed. At 21 degrees Celsius, a 1:1:1 feeding peaks in roughly 4 to 6 hours. At 26 degrees, the same feeding can peak in just 3 hours. At 18 degrees, it may take 8 hours or more. Our calculator estimates peak times based on your chosen ratio and a standard room temperature of 22 degrees Celsius. If your kitchen is warmer, expect a faster peak. If cooler, expect a slower one. Placing the starter near a warm oven or inside a proofing box can speed things up when needed.
Maintaining a Healthy Starter
A well-maintained starter should roughly double in volume between feedings and have a pleasant, tangy aroma. Signs of trouble include a strong acetone or nail-polish smell (too much acetic acid from under-feeding), a thin hooch layer of liquid on top (starter is hungry), or sluggish rising. To revive a neglected starter, feed it with a 1:2:2 ratio twice daily for 3 to 5 days. Use unbleached flour, as bleaching removes some of the nutrients wild yeast and bacteria need. Whole wheat or rye flour added at 10 to 20% of the total flour provides extra minerals that boost fermentation.