Sourdough Starter Calculator

A 1:1 ratio of flour to water (by weight) is the most common and creates a 100% hydration starter. This is the easiest to maintain and what most recipes assume. Some bakers prefer stiffer starters (a 2:1 flour-to-water ratio, around 50% hydration) for a more sour flavour and slower, less frequent feeding.

Typically you keep a small amount (20-50g) and feed it with equal or greater amounts of flour and water. The smaller the amount you keep relative to the feed, the more vigorous the fermentation will be.

If kept at room temperature, feed every 12-24 hours. If refrigerated, feed once a week. Before baking, take the starter out of the fridge and feed it 8-12 hours before you need it so it's active and bubbly.

Yes, and many bakers find wholemeal or rye flour creates a more vigorous starter because the bran and germ provide more nutrients for the yeast and bacteria. You can maintain with white flour and occasionally feed with wholemeal.

A mature, active starter should double in volume within 4-8 hours of feeding. The float test is a good indicator: drop a teaspoon of starter into water — if it floats, it is ready. The starter should also have a pleasant, mildly tangy smell and be full of bubbles throughout.