Hydration in sourdough

Hydration is a relationship between water and flour and is often expressed as a percentage. When someone says 100% hydration it refers to equal weights of water and flour. Often sourdough starters are 100% hydration meaning they are fed equal amounts of water and flour (but this is not always the case). Bread dough has a hydration percentage as well. Low hydration is usually 55-65% with a more closed crumb. A high hydration is 75% and up, resulting in a more open crumb (usually).

If you want to calculate the hydration you will divide the amount of water by the amount of flour in a recipe and multiply by 100.

The image above is 64% hydration. I used 300g water and 470g flour.