How Much Sourdough Starter Should You Use?

📖 7 min read · Updated August 2026

By SourdoughCalc Team

Use 20% ripe starter as your default, measured against the flour weight. For 500g of flour, that is 100g of starter. Lower the percentage for a longer, slower rise and raise it for a faster one.

Why Starter Percentage Matters

The starter percentage controls how fast your dough ferments. More starter means more yeast and bacteria at the start, so the dough rises faster. Less starter slows everything down, which gives you more scheduling flexibility and often more flavor.

What Does Each Percentage Look Like?

• 10% (50g per 500g flour): slow rise, best for overnight bakes at room temperature.
• 15% (75g per 500g flour): gentle rise, good for cooler kitchens.
• 20% (100g per 500g flour): the standard, balanced choice.
• 25% (125g per 500g flour): fast rise, use when you are short on time.
• 30%+: very fast, easier to over-ferment, harder to control.

What Starter Percentage Should Beginners Use?

Beginners should stick to 20%. It is forgiving, gives a predictable bulk fermentation, and matches most recipes. Once you learn how the dough feels at 20%, you can experiment with 10% for overnight schedules or 25% for same-day bakes.

How Do You Measure Starter by Percentage?

Weigh your flour first, then multiply by the percentage. For a 500g flour recipe at 20%, use 100g of ripe starter. Our free hydration calculator includes the starter field so you never have to do this by hand.

Does More Starter Make Bread More Sour?

Usually the opposite. A high starter percentage ferments quickly, producing a milder loaf. Deep sour flavor develops during a long, cool fermentation, which is why 10-15% starter with a cold proof is the more common route to tangy bread.

Starter Amount FAQ

Sources

• King Arthur Baking: Sourdough Starter Recipe
• The Perfect Loaf: Sourdough Starter Guide