To create your own sourdough starter you just need two basic ingredients — organic stoneground flour and water, and some basic equipment and conditions.
It is important that your flour is stone ground as the roller-milled process heats the flour up to temperatures that kill the naturally occurring wild yeast.
The conditions necessary to make a sourdough starter are a warm room. Not hot, not cold, just a room that is pleasant to be in.
A non-reactive container (sourdough starter is acidic and will react with certain metals) to make and store the starter. I prefer glass but plastic is fine too.
A whisk to incorporate air – you can use a whisk if you want.
A breathable cover or a lid such as a clean tea towel, coffee filter, or a loose-fitting disposable shower cap.
You need to keep it in a space to catch your wild yeast with no other cultured foods nearby, or there will be a cross over and you might not get the yeast you need.
The easiest way to start is to put 150g of organic stone ground wholemeal flour and 150g of 34 C water in a large jar. Whisk the mixture vigorously to incorporate air because yeast likes oxygen to reproduce and cover it with your breathable lid.
Allow your mixture to sit in a warm place for 12 to 24 hours. Between the 12- or 24-hour mark, you might be lucky enough to see some bubbles, indicating that organisms are present, but if you don’t then don’t worry. Repeat the feeding by removing a cup full of the mixture, and replacing it with 75g of flour and 75g of water, this time at 28 degrees. Stir vigorously, cover, and wait another 12 to 24 hours. From now on you will need to remove half of the starter before every feeding and discard it, so the starter you do have can multiply in organisms without your jar overflowing.
If you are somewhere warm and using fresh wholegrain flour you will see activity quickly – after about 3–4 days. But if you are in more temperate climates then it can take 10–14 days. The sourdough starter should be beautifully bubbly.
If it is ready to use then it will double in size, the time it takes to do this depends on the kind of flour, the amount of water and the temperature.
In our school generally, the ambient temperature is about 22C.
Rye flour doubles in about 3 hours.
Wholegrain doubles in about 4 hours.
White roller-milled flour doubles in about 8 hours.
Once your starter does this, you have captured and bred enough yeasts and bacteria for your starter to be active enough to bake with.
