In a bowl, mix the starter and water until dissolved and homogenous. It should look like muddy water and smell beautifully yeasty and beery.
Next, add the flour and mix the dough, making sure all the water is absorbed into the dough.
Cover the bowl with plastic wrap or a wet towel.
Autolyse
Autolyse the dough for 1 hour. This will fully hydrate the dough and help develop the gluten.
Adding salt, resting and folding the dough
Add the salt and give the dough a good mix making sure the salt is all dissolved and taken up by the dough.
Wet your hands slightly and with confidence grab the dough from both sides and lift it up in one swift motion.
At this point, the dough will be hanging with two flaps dangling(for lack of a better description.
Let those two flaps fold in under the dough and repeat once more.
Cover and rest the dough for 30 minutes and repeat the folding and resting process three more times.
When these steps are complete you will notice your dough holding its shape more easily and it would be nice and pillow-like so be gentle with it.
Shaping the dough
Dump the dough out on a lightly floured surface. As always with bread, work with confidence even if you have little at this stage. This makes things less sticky and by the end of it, your pretend confidence will turn you into a super confident bread baking Jedi.
Once dumped onto the floured surface, grab the far ends together and fold them into the middle. Repeating all the way down until the bread looks like a wrapped up baby Moses.
Next, grab the long end and fold to the middle. Grab the other end and fold over the previous fold.
You now have something that looks like a tight roll. If you messed it up and it looks like a creature from hell. Don't worry!) Just rest the dough again for 20 minutes relaxing the gluten and try again. Sourdough bread baking is actually very forgiving.
Shape into a round loaf using a circular motion using both hands slightly ticked in underneath the dough. Try and keep the surface tension without tearing the dough.
Overnight ferment in the fridge
When you are happy with your shape. Grab a banneton or a bowl or loaf tin lined with an extremely well-floured towel or cloth.
If you skimp this stuff will stick. So flour it well. Pop the dough into the container you prepared.
Sprinkle the top generously with more flour.
Place the whole bowl into a plastic bag or cover with a shower cap. Give it a cuddle, kiss, draw it a face and leave it in the fridge overnight for about 10 hours and up to 24 hours.
Scoring/slashing and baking
Remove the dough from the fridge and leave at room temperature for 30 minutes.
In the meantime heat your oven to 250°C or 482°F and prepare a small metal container filled with water.
Place a baking tray into the oven to get nice and hot. I suggest doing this about 1 hour before baking to get everything piping hot.
After thirty minutes to an hour remove the baking tray from the oven.
Sprinkle the hot tray with semolina. Carefully invert your sourdough onto the floured tray.
Using a sharp knife or razor blade, score or slash the top of the loaf a few times. I suggest keeping it simple.
It helps to flour or dip the blade in water before slashing in order to give it a cleaner less sticky cut.
The cuts need to be at a 45-degree angle and about 2 cm deep. There are millions of ways to do this and everyone has their own favourite way. So just my suggestion and not set in stone. This is to make sure the loaf rises evenly.
Place the dough into the oven along with a metal tray/container filled with boiling water. Ice cubes will just cool down the oven and very slowly turn into steam so don't do that in case you saw it somewhere.
At this point, also sprinkle a bit of water onto the base of the oven creating instant steam.
Close the door quickly and bake for 15 minutes at 250°C or 482°F. Turn the oven down to 220°C or 428°F and bake for a further 15 minutes.
After this time, turn the loaf over and bake the bottom for another 10 minutes. In professional bakeries, this process is a bit different, but this recipe and method were developed with the average home kitchen and what the home baker would be comfortable with, in mind.
When done, remove and set onto a wire rack or cloth to cool down completely before slicing or storing.
Notes
5 Key points for success
Use an active starter.
Do not over or under ferment your dough.
Make sure to shape your dough well(tight) before putting it into the fridge.
If your fridge is very cold your dough might rise very slowly. Either let it go for up to 24 hours or let it proof a bit on the counter at room temp for a few hours until ready to bake.
Make sure your oven is very steamy and hot.
Slash/score your bread properly before baking.
Storage
Never slice hot bread fresh from the oven.
As soon as the loaf has cooled down you should seal it airtight and store it at room temperature. Storing bread in the fridge makes it go stale quicker.
A properly stored loaf will keep for up to 5 days. It will lose its crunch but will stay fresh and can be toasted to regain crispiness.
The best way to store bread long term is to slice it after it's cooled down and store it in the freezer sealed airtight.