Make your levain by taking 50 grams of your sour dough starter adding 50 grams flour and 50 grams warm water to a jar. Just lay lid on top and place in an enclosed barely warmed space (like an oven).
Tare your digital scale with a large mixing bowl. Add 450g of all-purpose flour and about 290g of your warm water (around 80–85°F is ideal for your first mix). Mix with a wooden spoon until combined. The dough will be somewhat dry, but it will get hydrated more soon. Cover the bowl with a towel and allow the dough to sit for about 30-45 minutes. This is called autolyse, and it's a good idea to properly hydrate the dough and for helping gluten form.
Turn on the digital scale with the large bowl of dough and tare to zero. Add 100g of active starter (bubbly and recently fed). Mix in the starter starting with a wooden spoon and then use your hand to scoop the dough off the sides of the bowl and incorporate into the dough. Tare the digital scale one more time and add 10g of salt with a splash of warm water if needed (use the remaining water, about 10 grams, only add if the dough is extremely dry).Use one hand to hold the bowl and the other to start pulling and turning the dough until it starts to come together and form a soft dough. If it feels too wet, add a few tablespoons of flour until the dough is pulling away from the bowl and not too sticky. Cover the bowl with a towel and allow the dough to sit for about 30 minutes in a warm spot (we use our convection oven warmed for a minute or two (without the dough inside) and then turned off).
After the dough has rested for 30 minutes, you can begin your stretch and folds. With wet hands, do a set of stretch and folds (lift a section of dough, stretch it upward, then fold it over). Turn the bowl a quarter turn and repeat 3–4 times. This builds surface tension and strengthens the dough.Cover again and let it rest in a warm spot (ideally 75–80°F). Repeat 2–3 more sets of stretch and folds every 30–60 minutes. After 4–6 hours of resting in the bowl (depending on the temperature of your kitchen), the dough should have visibly risen and become soft and puffy. That’s your first rise done.A colder kitchen (65 degrees and less) means you might need to let the dough rise much longer (8-10 hours). A warmer kitchen (75 degrees+) means you only need 2-6 hours. Look for the dough to double in size and be flexible in your schedule until you get used to how your dough rises in your own environment. Gently remove the dough to a lightly floured work surface. Fold the dough starting with pulling the top to the middle, then the bottom to middle, then each side to the center. Flip over and use your hands to rotate the dough and tuck it under, forming it into a ball and creating tension on top.This final shaping step is crucial! I skipped it many times early on and got flat loaves. Give your dough structure so it can rise beautifully in the oven.At this point, you can let the dough proof on the counter another hour before baking, or you can see below for the alternative second rise in the fridge. If you want bread the same day, do the final rise on the counter for 30 minutes to 1 hour at room temp and then bake the dough! Simply allow your shaped dough to rest on the counter for this second rise and then bake.If you want to give the dough more time to build flavor, your can place dough seam-side up in a proofing basket lightly dusted with flour or rice flour, covered with plastic wrap, a plastic bag, or a shower cap, and keep it in the fridge overnight. You can also use a bowl, banneton basket, or loaf pan lined with a damp towel or tea towel (the dough tends to stick to these a bit). Let it rise overnight for the final rise in the fridge (cold proof). Please note: If you use this method of proofing in the fridge, you will want to cut your first rise on the counter to about half the time (so you dough does not overproof). You don't have to proof your dough in the fridge, we just give you this option because many people want to wait until morning to bake or they want to try to increase flavor. We actually prefer doing the second rise on the counter for the half hour to hour, and the bread still comes out amazing. Preheat your Dutch oven (or cast iron skillet) inside your oven to 425°F. Let it heat for 30 minutes.Turn the dough onto a piece of parchment paper (or sprinkle flour in bottom), score the top of the dough with a razor blade, sharp knife, or bread lame (go about half an inch deep and make the cut about 3-4 inches long on the top center of the dough). This allows steam to escape for the dough to expand more upon baking. Place the dough into the hot Dutch oven or cast iron skillet. We use a cast iron skillet base with a cake pan top inside of our convection oven and it works just as well. Just make sure you have a cake pan that fits your cast iron skillet. This works great if you don't have a Dutch oven. Bake at 425°F:-Covered: 14 minutes. -Then turn the pot 180° and bake covered another 14 minutes.-Remove the cover, turn the pot 180°and bake uncovered 14 minutes.-Then turn the pot again back 180° and bake the final 14 minutes uncovered.That’s a total of 56 minutes for a crispy crust and fully baked interior. Use a thermometer to check the internal temperature—it should be around 200°-210°F. Or look for that golden crust coloring on top. The outer crust should be crispy. Let the bread cool in the Dutch oven or skillet for 10 minutes, then transfer to a rack or board to cool completely (about 1 hour). Resist the urge to cut into it too soon—this helps the crumb set.
