In a large bowl. weigh out the 302g of water and add the leaven. Disperse the leaven in the water.
Add the flour and mix until all the dry flour has been incorporated.
Cover the bowl with a cloth (I use a clean plastic shopping bag that will be big enough for my bowl and put the bowl inside the bag) and let rest for 40 to 60 minutes for the autolyse period.
After the autolyse period, sprinkle the salt over the dough, add the 22g of water and work the salt into the dough by massaging it with your fingers until the dough comes together again and all the water and salt has been absorbed. Cover and rest for 30 minutes.
Do 4 sets of Stretch & Folds, one every 30 minutes, covering the bowl after each Stretch & Fold.
After the last Stretch & Fold, let the dough rest for 2 to 4 hours for the Bulk Fermentation. The dough should nearly double in volume.
Turn the dough out onto a floured surface. Preshape the dough and let it rest for 30 minutes. Do the final shaping and put your loaf in a well-floured banneton, loaf tin or in a cloth-lined container. Place the covered loaf in the fridge for the final retarded proof.
The following morning, heat the oven to as high as it will go (around 250°C) without the thermofan. If you have a pizza stone you can heat that in the oven to help keep a stable temperature when you bake the bread. Otherwise, put a baking tray in the oven. If you are baking the bread in a Dutch Oven or cast iron pot, place the pot lid-on in the oven when you turn it on.
Once the oven has come to temperature, you can wait for another 10 to 15 minutes to ensure the oven is evenly warmed up or use an oven thermometer to check the oven temperature.
Remove your loaf from the fridge (no need to let it warm up first). Turn it out onto baking paper or a silicone baking mat and score the loaf with a razor blade held at a 30° angle.
Place the baking paper or mat onto the pizza stone / baking tray, or open the lid of your pot and carefully put the bread inside using oven gloves. Replace the lid and slide the oven rack into the oven.
Pour a cup of just-boiled water into an oven pan at the bottom of the oven (still using oven gloves and being careful to keep your face away from the steam). Quickly close the oven door and set a timer for 20 minutes.
After 20 minutes, crack the oven door open to release the steam, or remove the lid of the pot. Close the oven again and set the timer for another 20 minutes. If your loaf is browning quickly at this stage you can reduce the oven temperature to 220°C.
Remove the loaf from the oven and place on a wire cooling rack for 30 to 60 minutes to cool down. If you have done the baking process correctly you will see some blistering on the crust, a nice oven spring and you will hear cracking and hissing as the loaf cools down.
Once your loaf is completely cooled down it can be stored in a plastic bag in a bread bin and should stay fresh for 3 to 4 days. If there is still bread left after 3 days I slice it and freeze in a ziplock plastic bag to use for toasting.