Mix the Dough: In a sturdy mixing bowl, combine lukewarm water and active sourdough starter. Break up the starter into small, shaggy pieces using your hands or a spatula.
Add Flours and Salt: Add white flour, rye flour, whole wheat flour, caraway seeds, and salt. Mix until all ingredients are incorporated, and there are no dry bits. Cover the bowl and let the dough rest for 1 hour.
Stretch-and-Fold: After the rest, perform the first round of stretch-and-folds, gently stretching the dough and folding it over itself until the dough becomes tight (4-8 times).
Second Stretch & Fold (optional): After 30 minutes, repeat the stretch-and-fold process, making sure the dough becomes tight. This makes a total of 2 rounds of stretch-and-folds.
Bulk Fermentation: Let the dough rest until it has doubled in size. This could take anywhere from 4-12 hours, depending on the temperature of your house. If your house is cold, it will take longer, and if it’s warm, it will take less time.
Shape the Dough: After bulk fermentation, turn the dough onto the counter. Divide the dough into two equal portions using a scale or by eye. Shape each portion into a round ball and let it rest for 30 minutes. If the dough still feels tight after 30 minutes, let it rest for an additional 30 minutes.
Prepare Loaf Pans: Use either non-stick pans, grease with butter and flour your pans, or line with parchment paper.
Final Shaping: After resting, flip each dough ball over so the smooth side is down. Gently shape each loaf by folding in the sides and creating tension to form a strong oval loaf. Place the shaped dough seam side down into loaf pans. Repeat with the second loaf.
Cold Proof: Cover the loaf pans and place both loaves in the fridge for 8-24 hours for a cold proof. The longer the cold proof, the more complex the flavor.
Preheat the Oven: After the cold proof, preheat your oven to 500°F (260°C). Place a metal baking tray or muffin tin at the bottom of the oven to pour hot water into later to generate steam (this is optional but highly recommended for a crisp crust).
Score the Loaves: Once the oven is preheated, take the loaves out of the fridge. Lightly flour the loaves and score them with a sharp knife or lame.
Bake the Bread: Open the preheated oven and carefully place the loaves inside. If you added a steam tray, pour 1 cup of hot water into the vessel at the bottom of the oven immediately after placing the loaves in. Close the oven door to trap in the steam.
Lower the Temperature: Drop the oven temperature to 375°F (190°C) and bake the bread for 40-45 minutes, or until the crust is golden and crispy.
Cool the Loaves: Once baked, remove the loaves from the oven and place them on a cooling rack. Let them cool for at least 1 hour before slicing.
Enjoy: Once cooled, slice your light rye and caraway sourdough sandwich bread and enjoy with a generous amount of butter, or use it for sandwiches, toast, or any other delightful dish!