What is a 100% Hydration Sourdough Starter and is it the Best?

While there’s plenty of information out there about the hydration level of sourdough and the science behind it, you might notice a gap when it comes to understanding sourdough starter hydration.

Some recipes mention using a 100% hydration sourdough starter, but there’s not much explanation about the “whys” behind it.

What Does “100%” Stand for?

When we talk about different hydration levels for sourdough starter, we’re essentially talking about the balance between water and flour in the starter.

How To Easily Calculate the Exact Starter Hydration Percentage?

Suppose you’re feeding your starter with 100 grams of flour. – For an 80% hydration starter, add 80 grams of water (100 grams x 0.8 = 80 grams).

Why is a 100% Hydration Sourdough Starter the Norm?

The most common hydration level for a sourdough starter is 100%. This means that during each feeding, you add equal amounts of flour and water, resulting in a 100% hydration starter.

What Are Stiff Sourdough Starters and Why Do Some People Prefer to Use Them?

A sourdough starter becomes a “stiff starter” when it’s kept at lower hydration, typically around 80%.

What Are Liquid Sourdough Starters and Why Do Some People Prefer to Use Them?

In contrast, a “liquid starter” or “liquid levain” has a higher hydration level, typically around 120%, where the weight of water is greater than the weight of flour, resulting in a more liquid or thick pancake batter-like consistency.

Does the Type of Flour I Use Affect Sourdough Starter Hydration?

In theory? No. But in practice? Yes! Flour absorbency can vary significantly between different types of flour. Put simply, certain flours have a higher capacity to soak up water compared to others.

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