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BReAD LAB! Sourdough Loaf

Bread Lab! book cover

Get Ready to Bake

The first step in baking (and also in conducting scientific experiments) is getting your tools and ingredients together. Then, it helps to create a rough timeline for your recipe. This careful planning helps you prepare—both physically and mentally—for what’s ahead! Sourdough bread takes about 24 hours to make, from start to finish. But most of those hours are resting time for the dough—and for you—while the microbes do their work to make bubbles and build flavor.

What You Need

  • large bowl
  • measuring cups
  • measuring spoons
  • dough scraper
  • dish towels or plastic wrap
  • 8″ × 4″ loaf pan
  • nonstick spray or oil


  • starter
  • whole wheat flour
  • water
  • salt


Timeline for Baking

Sourdough Mix: 12–15 hours, mostly resting time

Bread Dough: 8–10 hours for mixing, kneading, folding, shaping, resting and baking

Sourdough Mix

  • 1 cup whole wheat flour
  • ½ cup water, warm to the touch
  • 1 TBSP active whole wheat sourdough starter (see above)

Mix all ingredients until there are no lumps or dry flour in the bowl. Cover with a clean, damp dish towel or plastic wrap and leave in a draft-free place at room temperature for 12–15 hours. When it is ready, the mix will have expanded to 2–2½ times its original size.

Bread Dough

  • 3 cups whole wheat flour
  • 1¾ cups water, warm to the touch
  • 2 tsp salt
  • All sourdough mix


Place the flour, water, salt and sourdough mix in a large bowl. Mix together just enough to combine the ingredients. Cover with a clean, damp dish towel or plastic wrap to prevent the surface from drying out and let rest for 20 minutes.


Place the dough on a clean work surface, no flour needed. Gently pull the edge of the dough that is closest to your body toward yourself until it won’t go any farther without tearing. Fold the dough in half, and then turn it 90 degrees clockwise. Use a dough scraper to loosen the dough if it sticks to your work surface. Continue to stretch, fold and turn the dough for 8–10 minutes. The dough will change over this time, getting stronger and sticking to the work surface less and less. Form the dough into a ball, and place it into a bowl that is lightly dusted with flour. Cover with a clean, damp dish towel or plastic wrap and leave in a draft-free place at room temperature for 45 minutes.


Scrape the dough onto a very lightly floured surface without tearing it. Gently stretch the edges from the center in four directions, as far as you can without tearing it. Starting with the edge closest to you, fold the stretched dough back to the center. Next, do this with the edge opposite you. Then, fold in the left edge, and finally, the one on the right. Dust the bowl with a little more flour and return the dough to the bowl with the smooth side up. Cover it with a clean, damp dish towel or plastic wrap, and let rest for 45 minutes. Repeat with folding process two more times, resting the dough for 45 minutes between each folding. After the third time, let the dough rest, covered, for one hour.


Lightly coat the inside of your loaf pan (8″ × 4″) with oil or a nonstick spray. Sprinkle your work surface lightly with flour. Put your dough on the floured surface with the smooth side down, being careful not to tear it. Lightly pat the dough down into a rectangle no wider than your loaf pan. Starting at one end, roll the dough into a log, pinching the end to seal it. Place the dough log into the pan with the pinched side down. Cover the pan with a clean, damp dish towel or plastic wrap and let the dough rise in a draft-free place for three hours.


Place your oven rack in the lower third of the oven. Preheat the oven to 450°F for 20-30 minutes before you are ready to bake. Uncover the loaf pan and place it in the oven. Close the oven door and lower the temperature to 425°F. Bake for 40–45 minutes or until the loaf is nicely browned on top. Remove the loaf pan from the oven, turn it out of the pan, and place on a wire rack to cool.

Have Fun!

Whole Wheat Sourdough Bread from Bread Lab! by Kim Binczewski and Bethany Econopouly ©2018