Add sourdough, yeast, salt, and water to a mixing bowl and mix well.

Gradually stir in the flour so the dough doesn’t become dry. Don’t underestimate how much the weather can affect bread baking. The dough should just start to pull away from the sides.

Place the dough in a clean bowl greased with neutral-tasting oil and cover the bowl with a shower cap or plastic wrap. Put the bowl in the refrigerator overnight.

Take the dough out of the refrigerator and turn it out onto a floured surface. Fold the dough under itself 4-6 times until you have a ball.

Let the dough rise on a piece of baking paper for 2-3 hours under a clean kitchen towel.

Preheat the oven to 250 degrees Celsius (482 degrees Fahrenheit) with fan. Let the baking tray heat up inside the oven.

Carefully lift the baking paper with the bread into the hot oven without burning yourself. You can use a pizza peel for help if needed.

Once the bread is in the oven, throw 1 deciliter of water into the bottom of the oven to create some steam. Be careful the steam doesn’t hit you.

Bake the bread for 20-25 minutes.

Take the bread out of the oven and let it cool on a wire rack.

The bread will have a hard crust and be airy and delicious inside.