Sourdough Recipe Converter

A common guideline is to use 20-30% of the flour weight in starter. For a recipe with 500g flour, use 100-150g of active starter. More starter means faster fermentation; less means a longer, more flavourful rise.

Your sourdough starter is a mixture of flour and water. When you add it to the dough, it contributes both. To keep the overall recipe balanced (same total flour, same total water), you subtract what the starter provides from the amounts in the main dough.

Starter hydration is the ratio of water to flour in your starter, expressed as a percentage. A 100% hydration starter has equal weights of flour and water (e.g. 50g flour + 50g water = 100g starter). A 75% hydration starter has less water (e.g. 57g flour + 43g water = 100g starter).

Sourdough is much slower. A yeasted bread might rise in 1-2 hours, while sourdough typically needs 4-8 hours at room temperature for bulk fermentation, plus 8-16 hours of cold retard in the fridge for flavour development.

A 100% hydration starter is 50% flour and 50% water by weight. So 200g of starter contains 100g flour and 100g water. Subtract these amounts from the flour and water in the original recipe. This calculator does this automatically when you enter your starter amount and hydration.