America's Test Kitchen Sourdough Bread Recipe: Science-Backed Crust and Crumb Mastery

This America's Test Kitchen sourdough bread recipe transforms baking from art to science—delivering a crispy, caramelized crust and an open, airy crumb every single time. 🔥 The secret lies in precise temperature control, strategic fermentation timing, and ATK's signature techniques like autolyse and stretch-and-folds that professional bakers swear by.

I've baked through countless iterations to perfect this method, and the results speak for themselves: bread so good you'll abandon store-bought loaves forever.

The process begins with a thriving sourdough starter (we'll show you how to test and maintain it), then moves to a three-stage fermentation that develops maximum flavor and structure.

What sets this recipe apart is the attention to detail—from accurate hydration percentages to exact proofing times—that ensures consistent, foolproof results regardless of your kitchen environment. No more guessing whether your loaf will turn out dense or underproofed.

By the time you pull that golden-brown masterpiece from your Dutch oven, you'll have achieved a restaurant-quality crust with a shatteringly crisp exterior and an open, tender crumb inside.

The aroma alone will have everyone gathering in the kitchen, and the flavor—tangy, complex, and perfectly balanced—will make this your new standard for homemade bread. This isn't just another sourdough recipe; it's the one that finally delivers professional-quality results at home.

Whether you're a seasoned baker or new to sourdough, this method breaks down each critical step with clear instructions and troubleshooting tips. We'll cover everything from starter maintenance to final baking, including optional variations like whole grain additions or seed toppings. Let's get started on your path to perfect sourdough.

Ingredients for america's test kitchen sourdough bread

Precision ingredients and professional techniques—this is how you bake sourdough like the pros.

The sourdough starter is your foundation—look for a lively, bubbly starter that doubles in 4-6 hours after feeding. King Arthur bread flour is worth the splurge for its high protein content, but Bobs Red Mill works too. Water temperature matters: too warm and fermentation speeds up; too cool and it slows down. Use a thermometer to hit 78°F. For the Dutch oven, Lodge is the gold standard—preheat it with the bread inside for even heat distribution. The wooden peel should be dry to prevent sticking during transfers.

No bread flour? All-purpose plus 1 tbsp vital wheat gluten gets you close. Running short on time? Instant yeast at 1/8 tsp can jumpstart fermentation, but the flavor won't be as complex. For scoring, a lame gives clean cuts, but a sharp razor blade works in a pinch—just be steady. The honey in the starter feed isn't just for sweetness; it boosts microbial activity and extends shelf life. If your starter's sluggish, feed it 1:1:1 (starter:flour:water) twice daily for 24 hours before baking. And yes, you can use a cast-iron skillet if you don't have a Dutch oven—just monitor the steam.

Starter keeps in the fridge for weeks—feed it weekly to maintain vitality. Flour stays fresh forever in the pantry, but toast the extra for croutons or panzanella. Pre-shape dough can chill up to 24 hours for easier handling. The baked loaf? Crust stays crisp for 3 days if stored in a paper bag—no need for plastic. Freeze slices for 3 months by wrapping tightly in foil. Pro tip: Use the discarded starter for pancakes or crackers—waste not, want not.

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

Let's bake a sourdough masterpiece with science-backed techniques for that perfect crust and open crumb.

In a small bowl, combine the 0.5 cup active sourdough starter with 1.75 cups water and 0.5 tsp honey. Mix until fully incorporated, then add 3 cups all-purpose flour and 1 cup King Arthur bread flour. Stir vigorously for 2 minutes until you achieve a shaggy, sticky dough that clings to the bowl.

Cover the bowl with a damp towel and let it rest at room temperature for 12-16 hours until it doubles in size and shows active bubbles throughout. This feeding jumpstarts fermentation and ensures your bread develops proper flavor and structure. The starter should smell tangy and slightly sweet—if it smells harsh or like vinegar, it needs more time to recover.

In a large mixing bowl, combine the fed starter with 1.5 tsp kosher salt. Add 1 cup ice water and mix until just combined—you're looking for a shaggy dough that comes together but still has some dry spots. This is called an autolyse, and it allows the flour to hydrate fully before gluten development begins.

Cover the bowl and let it rest for 30 minutes. During this time, the dough will relax and become more pliable. After 30 minutes, perform a series of stretch-and-folds every 30 minutes for 2 hours. 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 strong gluten strands that trap gas for a better rise and open crumb structure.

After the final stretch-and-fold, let the dough rest uncovered for 15 minutes to relax. Meanwhile, preheat the Dutch oven in the oven at 450°F for 30 minutes. This step is critical—you want the Dutch oven piping hot when you bake.

Transfer the dough to a lightly floured surface and gently shape it into a round boule. Cup your hands and press the dough into a tight ball, rotating as you go. Place the dough seam-side up in the preheated Dutch oven, sprinkle the 0.25 cup cornmeal on top, and cover with the lid. Let it ferment at room temperature for 1-2 hours, or until it has risen by about 50% and springs back slowly when poked.

Preheat the oven to 475°F with the Dutch oven still inside. Remove the lid and use the lame or razor blade to score the dough in a crosshatch pattern, cutting about ¼ inch deep. This controlled slash prevents an uncontrolled burst during baking and creates a beautiful, crispy crust.

Bake covered for 20 minutes, then uncover and bake for another 20-25 minutes until the crust is deep golden brown and the internal temperature reaches 205°F. The bread should sound hollow when tapped on the bottom. If the crust isn't brown enough after 20 minutes, broil for 1-2 minutes to finish it off.

Remove the bread from the Dutch oven and transfer it to a wire rack. Let it cool completely for at least 1 hour before slicing. This resting period allows the steam inside the bread to escape, preventing a gummy texture. The crust should be crisp and shatterable, while the crumb should be open and airy with a slight tang from the sourdough.

Slice with a serrated knife and serve warm. The flavor will continue to develop over the next 24 hours as the dough ferments further. Store leftovers wrapped in a cloth-lined bag at room temperature for up to 3 days, or freeze for longer storage. This method ensures a bakery-quality loaf every time—crusty outside, tender inside, with that unmistakable sourdough tang.

Pro cooking tips for great america's test kitchen sourdough bread

Autolyse Mastery

The autolyse step is where the magic begins—this 30-minute rest lets the flour fully hydrate and gluten relax before you start developing it. I always use ice water (about 34°F) for this stage to slow fermentation slightly, giving me more control over timing.