The first step to making sourdough (after making your starter, of course) is making the levain. It’s basically just making a baby starter from your original to bake with. Simply mix 3 tablespoons of mature starter, ⅔ cup of flour and ½ cup of room temperature water together in a mason jar, cover, and place in the oven with the light on and wait for it to rise.
About an hour before your levain is ready we want to perform a step called “autolyze,” but don’t worry, it’s just a fancy word and this step is simple! Before you start this step make sure your levain is ¾ of the way to doubled. Mix together all of the flour and 1 ½ cups of water (you’ll use the rest in a later step). You just want to mix it together with your fingers until everything is moistened. Cover and let rest until your levain is ready.
The third step is doing your float test. Take a tablespoon of your levain a drop it into a small bowl or cup of water, if it floats it's ready! If it doesn’t it means there is not enough gas and you need to leave it a while longer.
The fourth step is your bulk fermentation, which is the first rise of your bread; this process will take 4-5 hours in total. This step takes a while but involves very little work unlike traditional bread. To start you’ll dimple your dough with your fingers. Add ¼ cup of the levain on top of the autolyzed dough and work it through until smooth. You’ll do this by folding it over on itself until it’s a smooth consistent texture. Now let it rest for 15 minutes.
After it has rested, you’ll add the salt. To do this sprinkle the salt over the dough and add the leftover water from earlier. Dimple this in the same way you did the levain and once again keep folding until it’s a smooth dough. Then cover and place it back in the oven with the light on to keep it warm. After 30 minutes, remove from the oven and uncover. Wet your hands and place one hand under the dough and scoop it up and stretch just to the point it doesn’t rip and fold it over on top of itself. You’ll do this at four points of the dough (north, south, east, and west). Cover and place back in the oven for another 30 minutes.
Repeat this process 5 times at 30-minute intervals. After the last set of stretch and folds cover and let ferment for the rest of the time. You’ll know that it’s done when it has risen between 30-50 percent, jiggles when you shake the bowl, and has bubbles on the top of the dough, especially around the edges.
The fifth step is the shaping of your dough. You’ll start by lightly flouring your surface. Dump your dough onto your surface and lightly flour your hands. Perform the stretch and folds once again until your dough is a rough circle. Turn the dough over (a bench scraper is great for this but not necessary), cover and let rest for 15 minutes.
You’ll now want to prep your breadbasket (or bowl lined with a tea towel works just fine). Coat your basket or tea towel with rice flour (this keeps the dough from sticking).
Now back to your dough! This is where a bench scraper really comes in handy but again not necessary). Dust the top of your bread with bread flour and use the bench scraper (or your hand) to turn the dough over. Complete another set of stretch and folds and this time when your dough is in a ball turn the dough over on your work surface and cup your hands around the ball. Pull it towards you using both hands for 4-5 inches dragging it. This will tighten the ball up. Do this several times rotating the ball each time until the ball is tight and round, but don’t do it too many times or you’ll tear your dough!
Now lift your dough and drop it into your proofing basket with the seam side up, cover, and pop in the fridge for 8-10 hours.
You're almost there! This is the baking step. But first, you’ll place your Dutch oven into your oven and then preheat it to 500 degrees F. Take your dough out of the fridge and lay it on a small piece of parchment paper. Dust the top with a little flour and then score it with a sharp blade or a traditional lame. Make sure its deep so you get a nice “ear” once it's cooked.
Remove the Dutch oven (make sure you use mitts and be careful as it will be very hot). Carefully place the loaf and the parchment into the pot and place the lid back on. Place into the oven and bake for 25 min. Reduce the temperature to 400 degrees F and remove the lid. Bake for another 20 minutes. Remove from the Dutch oven and let rest for at least an hour to let cool. It’s tempting to cut right away but cutting too soon can make the bread gummy so be patient and let rest for at least an hour.