About 8-10 hours before mixing, feed your starter at 1:5:5. That means take 15g starter, 80g flour, and 80g water mix it and let it grow at room temperature.
If you'd like more sour bread, you can start earlier.
Mix the ingredients and bulk fermentation - The next day
Add bread flour, rye flour, and salt to a bowl. Mix it with your fingers until it's well-distributed.
Add 150g of sourdough starter and 500g of water.
If you want to, you can mix on a machine until the dough looks nice and cohesive. Then go straight to the rise.
Otherwise, mix with your fingers until no dry bits remain. Leave the dough to rest covered for 60 minutes.
At this point, you can choose to jump straight to the rise, making it a no-knead bread. Otherwise, you can do three sets of stretch and folds or coil folds spaced out by 30 minutes. Coil folds are best if you are making one loaf.
The rise - jump here for machine and no-knead
Put the dough in a see-through container where you can monitor the bulk. Let the dough rise by 25%.
DON'T USE TIME!! Time varies on many factors, so go by the rise, not time.
If you are bulking cold, below 21°C/70°F, let the dough rise 100%.If you are bulking at room temperature, around 21°C-25°C/70°F, let the dough rise 50%.If you are bulking warm, above 25°C/77°F, let the dough rise 25%.
Divide and pre-shape
If you are making one loaf and used coil folds, skip straight to final shaping.
Divide the dough into two equally sized pieces by cutting it with your bench scraper. Preshape both pieces of dough into a boule.
Let the dough rest on the counter for 20 minutes.
Final-shape the bread into boules or bâtards, depending on what you prefer. Boules are the easiest, so if you're new, go for that. Watch the video to see how you do both of them.
After each dough is shaped, dust a banneton with rice flour and add the dough. Instead of a banneton, you can use a bowl lined with a dish towel. They will, of course, only accommodate boules.
Add both bannetons to your fridge. Your fridge should be ice cold. Mine's set to 2°C/35.5°F. Let the bread retard for 4 to 48 hours. You don't have to cover the dough.
Bake the bread
Heat your oven to 230°C/450°F with dutch oven inside. Heat for 30 minutes to make sure both are completely saturated with heat.
Grab a dough from the fridge. Dust it with rice flour on the bottom and put your peel over the top.
Flip it over so the dough rests on the peel. Dust the top with more rice flour and distribute it with your hands. Score the dough.
Open the oven and take the top off the dutch oven. Grab the peel and add the dough to the dutch oven.
Put the top on, close the oven, and bake for 25 minutes.
Prepare the other bread, as above. Then open the oven and take the top off of the dutch oven. Move the bread in the dutch oven to the side, and then add the unbaked bread to the dutch oven.
Put the lid on and bake for 25 minutes. Then take out the finished bread and put it on a wire rack.
Take the top of the dutch oven and brown the other bread. Then take it out and put it on a wire rack. Let them both cool to room temperature.