In a large bowl, using your hands or a spoonula, combine the starter, water, and flours. The dough should be jagged and thick. Cover the bowl with a towel (or you could use plastic wrap or beeswax wrap), and allow the dough to rest for 6 hours. I usually start this in the morning, before I leave the house for the day, and allow it to rest on the counter until I get home. After about 6 hours (it can go for a bit longer, if needed), the dough should have spread and increased in size.
Step Two:
Add the water and the salt to the dough. To do this, fold the ingredients into the dough by grabbing the underside of the dough, stretching it , and folding the sides over and on top of the dough. This is all done within the bowl. Cover the bowl with the towel and set a timer for 3 hours.
During this 3 hour time period, every 30 minutes, return back to the dough to "knead" it or "turn it." To knead the dough, I use the method described in Tartine Bread, "...dip one hand in water to prevent the dough from sticking to you and then grab the underside of the dough, stretch it up, and fold it back over the rest of the dough. Repeat this action three times so that all the dough gets evenly developed. This is considered one turn." The goal is to knead or turn the dough 3-4 times during this resting period--I've found that every 30 minutes works well.
By the end of this step, the dough should have increased by 20-30%, if not let the dough rise for another hour. <--This may be particularly true during the winter if your home is very cold.
Turn the dough onto a well-floured countertop surface (I use extra spelt flour). If the dough feels unreasonably wet to you (the dough should be a "wet dough"), you can knead in 30 more grams of spelt flour. If it still feels too wet to work with, you can add 20 more grams of flour (up to 50 total grams of flour).
Using the same kneading/turning method, fold the dough together to form a ball. Sprinkle the top of the dough with extra spelt flour and cover the dough with a towel. Allow the dough to rest for 30 minutes. During this time the dough will flatten and spread, like a very thick pancake.
Step Three:
Now it's time to shape the dough and get it ready for a final rise. Before doing this, you'll need to prep a proofing basket.
Whisk together 50/50 whole wheat flour and white rice flour--I mix 1 cup of each flour and keep this in a dedicated container that I pull out for this step.
If you're using a proofing basket, mist the basket with water and generously sprinkle the basket with the flour mixture. If you don't have a proofing basket, place a dish towel in a medium-size bowl, mist the towel with water and generously sprinkle the towel with the flour mixture. (The water misting helps the flour stick to the surface.)
Now it's time to shape the dough into what Tartine describes as a "neat package." To do this, fold one side of the dough (the side near you) up and over the center of the dough. Stretch out the dough to your right and fold the dough up and over the last fold. Repeat this with the left side. Now fold the dough "in the back" (furthest from you, I don't know what else to call this part) up and over the previous folds. At this point, you should have a compact dough ball. Gently roll the dough away from you, creating a smooth ball, and dust the top of the ball with some of the wheat and rice flour blend.
Let the dough rest for a minute, and then place your hand under the dough and drop it in prepared basket (with the floured top now at the bottom). Cover the basket with a towel, or plastic wrap or beeswax wrap, dust the top with a bit of the wheat and rice flour mixture, and place it in the fridge. Let the dough rest in the fridge for 12 hours before baking. Alternatively, you can leave the basket on the counter, covered, and let it rest for only 3-4 hours before baking.
Step Four:
To bake the bread, preheat the oven to 500F and place a Dutch oven, with a lid, in the oven. Remove the bread from the fridge and allow it to rest on the counter (at least 30 minutes before baking). Once the oven reaches 500F, remove the Dutch oven from the oven. Flip the bowl upside down and drop the bread into the Dutch oven. Use a very sharp knife, or a bread lame, to make a couple of cuts on the top of the bread to allow steam to escape.
Place the lid on the Dutch oven. Reduce the oven to 450F. Bake the bread, with the lid on, for 24 minutes (this creates a natural steam oven). After 24 minutes, remove the lid and and bake the bread for 20 minutes.
Remove the Dutch oven from the oven, and then remove the bread from the Dutch oven. Place the bread on its side to cool.
Cool the bread before slicing and enjoying. Use a sharp bread knife to cut the bread.
*Try to use a starter that's been fed in the last 12 hours--so it's fresh and very active. After using some of the starter to make the bread, you'll want to feed your starter. You shouldn't need to dump any of the starter (since roughly 50% just went into your bread) before feeding. **The price on Amazon is much higher than what I pay in the store. I purchase the white spelt flour (and the rice flour) from Whole Foods. I believe the spelt flour costs $10 for the same bag. I've tried making this bread with both 100% whole wheat and stone ground spelt, and I don't care for either one. The texture is far to dense for me. You're welcome to try stone ground spelt, if desired, just know that the texture may be a bit more on the rustic side and the flavor may be, too. All-purpose flour is the flour Tartine Bread calls for in the book. Tartine Bread does offer a 100% whole wheat recipe in the book. Don't worry if the bread looks like it's a "flop" when you remove it from the bowl and drop it in the Dutch oven. It's okay! I've had this happen several times, usually because I didn't add enough flour to the proofing basket to prevent the loaf from sticking. The bread will be fine, don't mess with it in the hot Dutch oven. If you find that the dough continues to be difficult to remove from the proofing basket, try adding the 30 grams (up to 50 grams) of spelt flour during the step 2. As you practice the art of making sourdough bread, you'll learn what to expect at each stage, including what the dough should feel like and what it should look like. Just like with anything, the more you practice the better you get. You'll also be able to develop a schedule that works best for you. I begin with step one in the morning, set a timer, and then come home in the afternoon/early evening and start step two while I'm making dinner. After the dishes, I finish up on step two and step three. The next morning I bake the bread (step four). During the school year, I make bread on Saturday and then bake the bread on Sunday. If your first loaf comes out too flat (the loaf spreads and doesn't hold its round shape), try adding the extra 30-50 grams of spelt flour during step 2, as talked about in the recipe. This should fix the issue. The bread will still be usable and tasty, even if it spreads and flattens while baking.