Day 1: Mix 100 g flour + 100 ml water + 1/2 teaspoon (2.5 ml) honey (in an open jar, keep at room temperature. You can cover the jar with a piece of cloth, so the mixture is exposed to the air).
Day 2: (You will already see a few small bubbles forming in the mixture. If not, they will appear shortly.) Add 100 ml of water and 100 g of flour to the mixture (add the water first and mix. Then add the flour to make it easier and quicker to obtain a smooth mixture; leave the jar open and at room temperature).
Day 3: (You should see bubbles; if not, do not mix, and wait until the next day). Add 100 ml of water and 100 g of flour to the mixture and mix thoroughly (keep the jar open and at room temperature).
Day 4: (Bubbles should appear in the mixture.) Repeat the previous step: add 100 ml of water and 100 g of flour to the mixture and mix thoroughly ( keep the jar open at room temperature).
Day 5: The sourdough starter is now mature and ready to use. You can use between 20% and 50% of the weight of the flour in the bread recipe. Keep the unused portion (sourdough starter) active by adding water and flour. You should put the sourdough in the refrigerator (4 to 6°C) and you can take it out as needed and keep it at room temperature for 2 to 4 hours before using it. To revive the sourdough, you can change the flour by mixing organic flours (white flour, whole wheat flour, rye flour, etc.).