America's Test Kitchen Sourdough Bread Recipe: Artisan Crust With Foolproof Fermentation

America's Test Kitchen sourdough bread recipe delivers the perfect balance of crispy crust and airy crumb, backed by years of scientific testing and baking expertise. The secret lies in precise fermentation control and oven techniques that ensure consistent results every time—no more failed loaves or dense bread.

I developed this method after testing dozens of variations, focusing on a predictable schedule that works for both beginners and experienced bakers.

This recipe simplifies the art of sourdough by breaking down each critical stage—maintaining your starter, bulk fermentation, shaping, and baking—with clear, step-by-step instructions. The key to success is patience: allowing the dough to ferment slowly at room temperature develops deep flavor while building structure.

We'll also cover troubleshooting common issues like oven spring and crust control, ensuring your loaf turns out perfectly every time.

The result is a golden-brown crust with an irresistible crunch and a soft, open crumb that's impossible to resist. This bread freezes beautifully for later use, making it perfect for meal prep or gifting.

Whether you're baking for a crowd or treating yourself to homemade bread, this foolproof method guarantees professional-quality results without the guesswork.

For those who want to experiment, we'll include variations like whole wheat dough and seeded crusts, along with tips for adjusting hydration levels. Let's get started on creating your best loaf yet.

Ingredients for america's test kitchen sourdough bread

Fourteen ingredients transform into the perfect sourdough loaf with crispy crust and open crumb.

The sourdough starter is non-negotiable—it's the heart of this recipe. King Arthur's sourdough starter is my go-to, but any active 100% hydration starter works. Look for bubbles and a tangy aroma; if it smells like vinegar, it's overfed. For beginners, maintain your starter on a consistent schedule: feed it equal parts flour and water every 24 hours. Whole Foods and Trader Joe's carry pre-made starters if you're in a rush, but homemade develops more complex flavors. The butter? Use European-style unsalted—Plugrá or Kerrygold melt beautifully for that golden crust. Keep it cold until you're ready to score the loaf.

No sesame seeds? Toasted sunflower seeds or flaxseeds work beautifully for that nutty crunch. Substitute poppy seeds with dried herbs like thyme or rosemary if you're going for a savory profile. The coarse sea salt is crucial—it dissolves slowly to create a concentrated flavor burst. Maldon flaky salt is ideal, but any coarse salt will do. For the flour, Bread flour can replace all-purpose, but add 0.25 tsp extra xanthan gum if your recipe calls for it. The ice water is a game-changer—it strengthens gluten development during the final stretch. If you're short on time, chill the dough in the fridge for 12 hours instead of bulk fermenting at room temperature.

This dough is a patience test—it needs 18-24 hours of fermentation for optimal flavor. Shape it into a batard or boule, then let it proof in the fridge overnight for even better results. The scored loaf keeps 3 days at room temperature wrapped in a clean kitchen towel, or 3 months frozen. For reheating, bake at 350°F for 10 minutes to restore that fresh-baked aroma. The butter scoring? Use a lamé or razor blade—it's worth the investment for clean cuts. Leftovers? Toast them—nothing beats sourdough toast with a schmear of that same European-style butter.

Step-by-step instructions for america's test kitchen sourdough bread recipe

This method delivers an open crumb, crisp crust, and perfect rise every time—no guesswork involved.

In a large bowl, combine the 0.5 cup active sourdough starter, 1.25 cups water, 3.5 cups all-purpose flour, 0.5 tsp granulated sugar, and 1.5 tsp diamond crystal kosher salt. I use a stand mixer with a dough hook attachment for this—it ensures even development without overworking the gluten. Mix on low speed for 2 minutes, then increase to medium for 5 minutes until the dough forms a shaggy mass that clings to the sides of the bowl.

Here's the thing—you want to avoid overmixing, which develops too much gluten and makes the bread dense. The dough should look slightly sticky but pull away from the bowl when you scrape it down with a spatula. If it's too wet, add 1 tablespoon of flour at a time until it reaches the right consistency. Once it passes the "windowpane test" (stretch a small piece—it should be thin enough to see light through without tearing), you're ready for the next step.

Transfer the dough to a lightly oiled bowl, cover it tightly with plastic wrap, and let it rest at room temperature for 1 hour. This initial rest allows the gluten to relax and the dough to absorb the starter's acidity. After 1 hour, perform a series of stretch-and-folds every 30 minutes for 2 hours total. To do this, wet your hands, grab one side of the dough, stretch it upward, and fold it over itself. Rotate the bowl and repeat—this builds strength without overworking.

After the final stretch-and-fold, let the dough rest uncovered for 30 minutes in the bowl. You'll notice it puffs up slightly and develops small bubbles along the surface. This is your signal that the gluten has relaxed enough for shaping. The dough should now be jiggly when gently pressed—if it springs back too quickly, it needs more time. If it doesn't spring back at all, it's overproofed.

Lightly dust a clean surface with 0.25 cup cornmeal and turn out the dough. Pat it into a rough rectangle, then fold the long sides toward the center to create a log shape. Seal the seam by pressing gently with your fingers. Roll the dough away from you into a tight cylinder, tucking the ends under as you go. This creates surface tension that prevents the bread from spreading too much during baking.

Place the shaped loaf seam-side down in a lightly greased 9x5-inch loaf pan. Cover it with a damp towel and let it proof at room temperature for 1 to 1.5 hours, or until it has risen to about 1 inch above the rim of the pan. The dough should look domed and feel firm to the touch—press gently with your finger. If it springs back slowly, it's ready. If it springs back quickly, let it proof another 30 minutes.

Preheat your oven to 375°F with a baking stone or inverted baking sheet on the middle rack. Place a metal bowl filled with 0.25 cup ice water on the lower rack. Once the oven reaches temperature, carefully remove the loaf pan from the dough and transfer it to the preheated stone or sheet. Pour ½ cup of boiling water into the metal bowl on the lower rack—this creates steam that mimics a home oven's environment and gives you that coveted crisp crust.

Bake the bread for 35 to 40 minutes, until the top is deep golden brown and sounds hollow when tapped on the bottom. The internal temperature should reach 190°F at the center. If the top browns too quickly, tent the loaf with aluminum foil after 20 minutes to prevent over-browning. The bread is done when it pulls away from the sides of the pan with ease and has a crisp, crackly crust.

Remove the bread from the oven and let it cool in the pan for 10 minutes. While it's still warm, brush the top generously with 0.25 cup unsalted butter, melted and strained to remove any milk solids. This step isn't just for flavor—it creates a glossy, tender crust. Immediately sprinkle 1 tbsp sesame seeds and 1 tbsp poppy seeds evenly over the top, pressing them lightly so they adhere. Finish with a final sprinkle of 1 tbsp coarse sea salt for a burst of flavor.

Transfer the bread to a wire rack to cool completely. The crust will firm up as it cools, developing that perfect balance of crispness and chewiness. Slice it thickly—this bread is best enjoyed fresh from the oven, with a generous slather of that buttery crust melting into every bite. The open crumb and tangy flavor from the sourdough starter will make it the star of your table.

Flavor customization for america's test kitchen sourdough bread

Sweet Variations

For a touch of sweetness, swap 0.5 tsp granulated sugar for 1 tsp honey or maple syrup in the dough. This enhances the crust's caramelization while keeping the crumb tender. I love adding 1 tbsp cinnamon to the dough for a subtle warmth—it pairs beautifully with apple butter or jam.

For a festive twist, sprinkle crushed candy cane pieces or toasted coconut flakes on top before baking. 🍯

Savory Herb Crust

Transform your sourdough into a savory masterpiece by mixing 1 tbsp dried rosemary or thyme directly into the dough. For extra depth, add 1 minced garlic clove to the butter you brush on after baking.

Finish with flaky sea salt and crushed black pepper for a rustic, herby loaf perfect for charcuterie boards. I often use Maldon flaky salt for that signature crunch.

Whole Wheat Boost

Replace 1 cup all-purpose flour with whole wheat flour for added fiber and nuttiness. To prevent a dense crumb, reduce the water by 1 tbsp and extend bulk fermentation by 1-2 hours.

The whole wheat absorbs moisture differently, so monitor closely. For texture, add 1 tbsp vital wheat gluten to mimic the elasticity of all-purpose flour. 🌾

Seeded Crust Options

Beyond sesame and poppy seeds, try toasted pumpkin seeds for a nutty crunch or crushed pistachios for a luxurious touch. For a Mediterranean twist, mix 1 tbsp each of sesame, poppy, and sunflower seeds with 1 tsp dried oregano before sprinkling.

Press seeds firmly into the warm crust so they stick—this ensures every bite has texture and flavor.

Spiced Variations

Infuse your dough with bold flavors by adding ½ tsp smoked paprika or 1 tsp cumin for a smoky depth. For a Middle Eastern-inspired loaf, mix 1 tsp za'atar into the dough and top with toasted za'atar and olive oil after baking.

These spices elevate the bread's complexity without overpowering the natural tang of the sourdough starter. 🌶️

Gluten-Free Adaptation

For a gluten-free version, replace all-purpose flour with a 1:1 gluten-free baking flour blend (like King Arthur's) and add 1 tsp xanthan gum. Reduce hydration by 1 tbsp and extend bulk fermentation to 24 hours in the fridge.

The dough will be stickier, so use wet hands when handling. Expect a denser crumb but still delicious with the right toppings.

Frequently asked questions