FlourScaleWhat a feeding ratio means
A sourdough feeding ratio is written as starter : flour : water, by weight. A 1:2:2 feed means one part of existing starter mixed with two parts flour and two parts water — for example 25 g starter, 50 g flour and 50 g water. The first number is the "seed"; the other two are the food. Equal flour and water gives a 100% hydration starter, the most common kind.
The ratio controls how fast your starter peaks. With a 1:1:1 feed the yeast and bacteria have relatively little food to get through, so the starter rises and peaks quickly. At 1:5:5 or 1:10:10 the same amount of culture has much more food, so it takes longer to peak and stays at its best for longer. That makes higher ratios useful for overnight feeds, warm kitchens, or when you want a milder, less acidic levain.
How to use the calculator
Tap a common ratio or type your own parts. Then choose a mode. Make a total amount divides the total you want by the number of parts: a 1:2:2 ratio has 5 parts, so 150 g total means 30 g per part. Feed starter I have starts from the starter weight you are keeping and multiplies the flour and water accordingly. The result also shows the resulting starter hydration and a rough peak-time range at about 24°C (75°F).
Worked example
You need 110 g of levain for tomorrow morning and want it to peak in roughly 10 hours, so you choose 1:5:5.
- Total parts = 1 + 5 + 5 = 11
- One part = 110 ÷ 11 = 10 g
- Mix 10 g starter + 50 g flour + 50 g water
Hydration of the result = 50 ÷ 50 = 100%.
Choosing a ratio
- 1:1:1 — fast; often peaks in about 4–6 hours at room temperature. Good for a starter you will use the same afternoon.
- 1:2:2 to 1:3:3 — a balanced daily feed for many kitchens.
- 1:5:5 to 1:10:10 — slow; useful overnight or in summer. Also helps a starter that has become very sour.
- Stiff (e.g. 1:5:2.5) — 50% hydration; ferments more slowly and tends to taste milder.
The peak times above are general guidance, not a rule. Flour type, temperature and the health of your culture all matter: whole grain and rye flours speed fermentation, and every 4–5°C change in temperature makes a noticeable difference. Watch for a domed top that has roughly doubled, lots of bubbles, and a pleasant tangy smell. Keep a small amount of starter, feed what you need, and discard (or bake with) the rest.