How to Calculate Sourdough Hydration Percentage

(...And why it matters)

Understanding hydration percentage is one of the most powerful skills in sourdough baking. This single number affects everything from dough handling to crumb structure, yet many bakers find the calculations confusing, especially when factoring in their starter. Let's demystify hydration math and explore why mastering this concept will transform your baking.

What Is Hydration Percentage?

Hydration percentage represents the ratio of water to flour in your dough, expressed as a percentage. A dough with 500g flour and 350g water has 70% hydration (350 ÷ 500 × 100 = 70%). This simple calculation is easy when using dried commercial yeast, but becomes more complex when you add sourdough starter, which contains a ratio of both flour and water.

Common hydration ranges for artisan sourdough:

• 65-70%: Easier to handle, tighter crumb, good for beginners
• 70-75%: Balanced handling and open crumb (most recipes)
• 75-80%: Sticky dough, very open crumb, requires experience
• 80-85%: Very sticky, extremely open crumb, advanced techniques needed

The Basic Calculation (Without Starter)

For commercial yeast breads, hydration calculation is straightforward:

Hydration % = (Total Water ÷ Total Flour) × 100

Example:

• 500g flour
• 375g water
• Hydration = (375 ÷ 500) × 100 = 75%

Including Sourdough Starter in Your Calculations

This is where many bakers get confused. Your sourdough starter contains both flour and water that must be included in the total hydration calculation. The key is knowing your starter's hydration percentage.

For 100% Hydration Starter (Most Common)

A 100% hydration starter contains equal parts flour and water by weight. If you feed your starter using equal amounts (like 20g starter + 50g flour + 50g water) you have 100% hydration.

To calculate flour and water in 100% hydration starter:

• Flour in starter = Starter weight ÷ 2
• Water in starter = Starter weight ÷ 2

Example using Yeast Coast Sourdough's Simply White Sourdough recipe:

• 120g starter (100% hydration) = 60g flour + 60g water
• 500g flour (in recipe)
• 350g water (in recipe)

Total flour = 500g + 60g = 560g
Total water = 350g + 60g = 410g
True hydration = (410 ÷ 560) × 100 = 73.2%

For Different Starter Hydrations

Not everyone maintains a 100% hydration starter. Here's how to calculate for any starter hydration:

Step 1: Determine your starter's hydration If you feed 1:3:2 (starter:flour:water), your maintained starter has:

• 3 parts flour
• 2 parts water
• Hydration = (2 ÷ 3) × 100 = 67%

Step 2: Calculate flour and water in your starter For a 67% hydration starter:

• Flour = Starter weight ÷ (1 + 0.67) = Starter ÷ 1.67
• Water = Flour × 0.67

Example with 120g of 67% hydration starter:

• Flour = 120g ÷ 1.67 = 72g
• Water = 72g × 0.67 = 48g

Why Hydration Percentage Matters

Understanding hydration affects every aspect of your baking:

Dough Handling:

• Lower hydration (65-70%) = easier shaping, less sticky
• Higher hydration (75-85%) = requires wet hands, bench scraper essential

Crumb Structure:

• Lower hydration = tighter, more uniform crumb
• Higher hydration = open, irregular holes

Fermentation Time:

• Higher hydration doughs ferment faster
• More water means more enzyme activity

Crust Development:

• Higher hydration = thinner, crispier crust
• Lower hydration = thicker, chewier crust

Common Hydration Calculation Mistakes

Mistake 1: Ignoring starter altogether Many recipes list hydration without including starter, leading to unexpected dough texture.

Mistake 2: Assuming all starters are 100% hydration If your starter isn't 100% hydration, your calculations will be off.

Mistake 3: Not accounting for flour absorption Whole wheat and rye flours absorb more water than white flour, effectively lowering hydration.

Practical Hydration Calculator Table

Here's how different starter amounts affect final hydration using our Simply White recipe as a base:

Adjusting Hydration for You:

Your ideal hydration depends on multiple factors:

Flour Type:

• Bread flour can handle 5-10% more water than all-purpose
• Whole wheat needs 5-10% additional water
• Fresh-milled flour requires even more hydration adjustment

Climate:

• Dry climates may need 5% higher hydration
• Humid environments may need 5% lower hydration

Experience Level:

• Beginners: Start with 65-70% hydration
• Intermediate: Comfortable with 70-75%
• Advanced: Can handle 75-85%+

Troubleshooting Hydration Issues

"My dough is too sticky to handle"

• Your true hydration may be higher than calculated
• Try reducing water by 25g (5%) next time
• Use wet hands and a bench scraper when shaping
• Practice coil folds instead of traditional kneading

"My bread is dense with a tight crumb"

• Consider increasing hydration by 25-50g water
• Ensure proper fermentation time
• Check starter strength (weak starters struggle with higher hydrations)

"Recipe hydration doesn't match my results"

• Verify your starter's hydration
• Check if recipe includes starter in calculations
• Consider flour differences (brand, type, age)

The Yeast Coast Sourdough Advantage for Consistent Hydration

When you're learning hydration calculations, consistency is key. The Yeast Coast Sourdough Superstarter™ rehydrates predictably to 100% hydration when following our maintenance instructions, eliminating one variable from your baking equation. Our included recipe cards account for starter hydration in all calculations, so you'll always know your true dough hydration.

With our 175-year-old culture's proven strength, you can confidently experiment with different hydration levels, knowing your starter can handle everything from stiff 65% doughs to slack 80% ciabatta-style breads.

Quick Reference Formula Card

For 100% hydration starter:

• Total Flour = Recipe Flour + (Starter ÷ 2)
• Total Water = Recipe Water + (Starter ÷ 2)
• Hydration % = (Total Water ÷ Total Flour) × 100

For other starter hydrations:

1. Flour in Starter = Starter Weight ÷ (1 + Starter Hydration as decimal)
2. Water in Starter = Flour in Starter × Starter Hydration as decimal
3. Calculate totals and divide as above

Start Calculating with Confidence

Understanding hydration percentage transforms you from recipe follower to recipe creator. Start with your favorite recipe, calculate its true hydration, then adjust by 5% to see how it changes your bread. Keep notes on your preferences for different bread styles.

Remember: there's no "perfect" hydration, only what works best for your flour, environment, and preferences. Master the math, and you'll bake with confidence every time.

Next: Sourdough 101 the Absolute Beginner's Guide