Sourdough Starter Calculator

Calculate flour and water needed per feeding to build enough sourdough starter for your recipe.

Results

Visualization

How It Works

Building a levain (sourdough starter for a recipe) requires planning feeds so you have enough ripe starter at bake time. The feeding ratio determines how fast or slow the starter ferments -- higher ratios (1:5:5) take longer but produce milder flavor.

The Formula

Final Feed: Seed = Needed x (StarterPart / TotalParts), Flour = Needed x (FlourPart / TotalParts). Initial Seed = Needed / (Multiplier ^ Feeds).

Variables

Starter = seed culture, Flour = fresh flour added, Water = fresh water added, Ratio = proportions of each.

Example

Need 100g starter with 1:1:1 ratio, 2 feeds: initial seed = 11g, each feed triples. Feed 1: 11g + 11g flour + 11g water = 33g. Feed 2: 33g + 33g + 33g = 99g (round to 100g with buffer).

Tips

  • A 1:1:1 ratio peaks in 4-6 hours at 75 F. A 1:5:5 ratio takes 10-14 hours.
  • Always make 10-20% more starter than your recipe calls for -- you lose some to the jar.
  • Feed your starter with the same type of flour you plan to bake with for best results.
  • Use warm water (80-85 F) to speed fermentation or cool water (65 F) to slow it down.
  • The starter is ready when it has doubled in size and has a domed top that just starts to flatten.