How to make sourdough starter from scratch

With just 2 ingredients, love, warmth, time and luck, you can easily grow your sourdough starter at home!

Kitchen scale
2-3 Glass jars with lids heat-resistant, canning jars, 500g (small), 750g (Large)
2-3 Spoons Long-enough for the jars
1-2 Bowls
1 Permanent marker

50 g Warm water ~ 40 °C
50 g Organic whole grain rye flour Any other high-quality whole grain/ whole wheat flour of your choice
Sourdough Starter Not on day 1
Boiling water To sterilise all utensils

In a small clean jar, add 50g of organic whole grain rye flour into 50g of warm water.
Mix the ingredients with a clean spoon until you get a smooth texture.
With the help of a second spoon, smoothen the top of the mixture until you get a flat surface. Mark the height of your mixture with a permanent marker.
Gently place the lid on the jar, without screwing the lid. Simply cover the mixture with the lid.
Place the jar in a warm place (between 26 °C and 30 °C) for 24 hours. It is a good sign, if you start seeing tiny bubbles in the starter.
The height of the sourdough starter should double. In addition, there should be many tiny little bubbles in the starter.

In a large clean jar, add 50g of whole grain rye flour into 50g of warm water. Thereafter, add all the sourdough starter from Day 1 into the large jar.
Mix the ingredients with a clean spoon until you get a smooth texture.
With the help of a second spoon, smoothen the top of the mixture until you get a flat surface. Mark the height of your mixture with a permanent marker.
Gently place the lid on the jar, without screwing the lid. Simply cover the mixture with the lid.
Place the jar in a warm place (between 26 °C and 30 °C) for about 24 hours. Sometimes, it takes shorter time for the sourdough starter to rise, if you see the signs from the next step. Then, you can proceed to Day 3.
The height of the sourdough starter should at least be doubled. In addition, there should be many little bubbles in the starter (larger than that from Day 1). The starter has risen to its maximum and it has fallen slightly. Check the sides of the jar for sourdough streaks.

In a small clean jar, add 50g of whole grain rye flour into 50g of warm water. Thereafter, add 25g of the sourdough starter from Day 2 into the jar. Discard the rest of the sourdough.
Mix the ingredients with a clean spoon until you get a smooth texture.
With the help of a second spoon, smoothen the top of the mixture until you get a flat surface. Mark the height of your mixture with a permanent marker.
Gently place the lid on the jar, without screwing the lid. Simply cover the mixture with the lid.
Place the jar in a warm place (between 26 °C and 30 °C) for about 10 to 24 hours. Sometimes, it takes shorter time for the sourdough starter to rise, if you see the signs from the next step. Then, you can proceed to Day 4.
The height of the sourdough starter should at least be doubled. In addition, there should be many bubbles in the starter (larger than that from Day 2). The starter has risen to its maximum, and it has fallen slightly. Check the sides of the jar for sourdough streaks. The sourdough starter should start to produce a mild, fruity, citrusy smell.

In a small clean jar, add 50g of whole grain rye flour into 50g of warm water. Thereafter, add 25g of the sourdough starter from Day 3 into the jar. Discard the rest of the sourdough.
Mix the ingredients with a clean spoon until you get a smooth texture.
With the help of a second spoon, smoothen the top of the mixture until you get a flat surface. Mark the height of your mixture with a permanent marker.
Gently place the lid on the jar, without screwing the lid. Simply cover the mixture with the lid.
Place the jar in a warm place (between 26 °C and 30 °C) for about 6 to 12 hours. Sometimes, it takes shorter time for the sourdough starter to rise, if you see the signs from the next step. Then, you can proceed to Day 4.
The height of the sourdough starter should at least be doubled. In addition, there should be many bubbles in the starter. The starter has risen to its maximum and fallen slightly. Check the sides of the jar for sourdough streaks. The sourdough starter should start to produce a mild, fruity, citrus smell.
Repeat the steps from Day 4 for another 2 to 3 times. Thereafter, keep the jar with the lid (loosely place on top of the jar) into the refrigerator. Feed your sourdough about once a week or when you need to bake. A fresh sourdough starter is needed for baking, since old sourdough starter does not effectively rise bread dough.

In a small clean jar, add 50g of whole grain rye flour into 50g of warm water. Thereafter, add 10g of the sourdough starter into the jar. Do not throw away the rest of the old sourdough starter until the new sourdough starter has grown successfully. In case, the new sourdough starter did not work out, you can refresh the old sourdough starter again.
Mix the ingredients with a clean spoon until you get a smooth texture.
With the help of a second spoon, smoothen the top of the mixture until you get a flat surface. Mark the height of your mixture with a permanent marker.
Gently place the lid on the jar, without screwing the lid. Simply cover the mixture with the lid.
Place the jar in a warm place (between 21 °C and 26 °C) for about 6 to 12 hours. Sometimes, it takes shorter time for the sourdough starter to rise, if you see the signs from the next step.
The height of the sourdough starter should at least be doubled. In addition, there should be many bubbles in the starter. The starter has risen to its maximum and fallen a little. Check the sides of the jar for sourdough streaks. The sourdough starter should start to produce a fruity and citrusy smell. As your starter ages, the smell of it intensifies as well.
Immediately, keep the jar with the lid (loosely place on top of the jar) into the refrigerator. Feed your sourdough about once a week. You can either discard the old sourdough or make the best out of it.