how to calculate hydration of sourdough

Sourdough baking is an art and a science, and one of the most crucial elements to master is hydration. Understanding and accurately calculating your sourdough's hydration percentage is key to controlling your dough's texture, extensibility, and ultimately, the quality of your finished loaf. But what exactly is hydration, and how do you calculate it?

What is Sourdough Hydration?

In baking, hydration refers to the ratio of water to flour in your dough, expressed as a percentage. A higher hydration means more water relative to flour, resulting in a stickier, more extensible dough, often leading to an open, airy crumb. Conversely, lower hydration results in a stiffer dough, easier to handle but potentially yielding a denser crumb.

It's important to distinguish between "dough hydration" and "total hydration." When talking about sourdough, the starter itself contributes both flour and water to the overall dough. Therefore, a comprehensive calculation considers all flour and all water from all sources.

The Key Components: Flour, Water, and Starter

To calculate sourdough hydration, you need to know the weight of three main components:

• Flour: The total weight of all dry flour added to your dough.
• Water: The total weight of all liquid water added to your dough.
• Sourdough Starter: The weight of your active sourdough starter.

The trickiest part is the starter. A typical sourdough starter is 100% hydration, meaning it's made with equal parts flour and water. So, if you add 100g of 100% hydration starter, you're essentially adding 50g of flour and 50g of water to your dough.

The Sourdough Hydration Formula

The general formula for calculating total sourdough hydration is:

Total Hydration (%) = (Total Water Weight / Total Flour Weight) * 100

Let's break down how to find "Total Water Weight" and "Total Flour Weight":

Step 1: Calculate Water from Starter

If your starter is 100% hydration, then the water in your starter is half its weight. If your starter has a different hydration (e.g., 80% hydration), you'll need to calculate it:

Water from Starter = Starter Weight * (Starter Hydration Percentage / (100 + Starter Hydration Percentage))

For a 100% hydration starter, this simplifies to:

Water from Starter = Starter Weight * 0.5

Step 2: Calculate Flour from Starter

Similarly, the flour in your starter is the other half (for 100% hydration starter) or calculated as:

Flour from Starter = Starter Weight * (100 / (100 + Starter Hydration Percentage))

For a 100% hydration starter, this simplifies to:

Flour from Starter = Starter Weight * 0.5

Step 3: Calculate Total Water Weight

Add the water you directly added to your dough and the water contributed by your starter:

Total Water Weight = Added Water Weight + Water from Starter

Step 4: Calculate Total Flour Weight

Add the dry flour you directly added to your dough and the flour contributed by your starter:

Total Flour Weight = Added Flour Weight + Flour from Starter

Step 5: Calculate Total Dough Hydration

Now, plug these totals into the main hydration formula:

Total Dough Hydration (%) = (Total Water Weight / Total Flour Weight) * 100

Example Calculation

Let's say your recipe calls for:

• 500g Bread Flour
• 350g Water
• 100g Sourdough Starter (100% hydration)

1. Water from Starter: 100g * (100 / (100 + 100)) = 100g * 0.5 = 50g
2. Flour from Starter: 100g * (100 / (100 + 100)) = 100g * 0.5 = 50g
3. Total Water Weight: 350g (added) + 50g (from starter) = 400g
4. Total Flour Weight: 500g (added) + 50g (from starter) = 550g
5. Total Dough Hydration: (400g / 550g) * 100 = 72.73%

So, the total hydration of your dough is approximately 73%.

Why Does Hydration Matter So Much?

The hydration level profoundly impacts several aspects of your sourdough:

• Dough Handling: Higher hydration doughs are stickier and more challenging to handle for beginners but can develop greater extensibility. Lower hydration doughs are easier to work with.
• Crumb Structure: Higher hydration often leads to a more open, airy, and irregular crumb, which is highly prized in artisan sourdough. Lower hydration tends to produce a tighter crumb.
• Flavor Development: While not directly affecting flavor, the environment created by hydration can influence fermentation and enzyme activity, indirectly impacting flavor.
• Crust: Hydration affects how the crust forms and crisps during baking.

Adjusting Hydration for Your Needs

As you gain experience, you'll learn to adjust hydration based on your flour type (some flours absorb more water than others), ambient humidity, and desired outcome. Always remember that these calculations provide a baseline; feeling the dough is ultimately the best guide.

Use the calculator above to quickly determine your dough's hydration and empower your sourdough journey!