For the Levain:

1. Mix all the ingredients until well combined. Cover with a lid. I like to place an elastic band around the top of the levain at the beginning of the feed so I can monitor its growth. This build should take about 10-12 hours at 22.2°C/72°F.

For the Fermentolyse:

1. Add the water and levain to the mixing bowl.
2. Add the flour to the bowl and mix well until there are no dry bits.
3. Cover and leave in a warm place ideally the same as your levain build.
4. Autolyse for 1 hour with an ideal temperature of 26°C/80°F.

Mixing the Dough:

1. Using the remaining water mix in the salt to the dough by hand. This should take about 5 minutes.
2. Once the salt is added allow the dough to rest for 20-30 minutes.
3. Add the olive oil and mix in by hand.
4. Place the dough in a lightly oiled container or bowl and cover with a lid. 
5. Desired Dough Temperature – 27°-28C/80-82°F

Bulk Fermentation:

1. Bulk ferment the dough for 3 hours.
2. Give the dough 3 stretches during the bulk fermentation.
3. After the last fold place the dough in the fridge until the next morning.

Divide and Pre-Shape:

1. Take the dough container out of the fridge and allow the dough to come to room temperature for about 1 hour.
2. Remove the dough from the container onto the table and pre-shape round.
3. Place the dough into a lightly oiled baking pan cover and let relax for 3-5 hours.
4. This time will depend on your ambient temperature.

Final Shape:

1. Using lightly oiled hands gently put them under the dough and stretch it towards the corners of the pan. Be careful not to pull, degas or tear the dough.
2. Pour some olive oil onto the surface of the dough and using your hands rub the dough to cover it with the oil.
3. With the tips of your fingers, press down into the pan trying to feel the bottom of the pan without pressing all the way through the dough.
4. Sprinkle the dough with maldon salt.

Baking:

1. Preheat the oven to 246°C/475°F for a still oven or 237°C/460°F for a convection oven.
2. Bake the focaccia for 25-30 minutes until it pulls away from the sides and is golden brown.
3. Check the dough after 20 minutes and rotate the pan if necessary.
4. When fully cooked, remove the focaccia from the oven and slide the dough onto a cooling rack.
5. Let the sourdough focaccia cool completely before slicing.