When I start a new sourdough starter, I always use organic wholemeal flour. In this case I used a spell flour. A organic oatmeal is more likely to contain the bacterias and the wild yeast that we need scale of 40 grams of flour and 40 grams of water and give it a good mix on to all the flowers been hydrated. Now cover your jar with a lid very loosely and set it aside for one to three days. After a day or so you should start to see some bubbles forming on the top of the sourdough. And if your sourdough starts to separate a little bit, and there's some brown water on top that is completely normal.
Your sourdough should now smell slightly acidic, and maybe a little bit of beer and wheat. At this stage, we will feed the sourdough again. And we continue to use a whole meal in this startup phase, this time we use 60 grams of wholemeal flour and 60 grams of water. Give that a good mix and cover it loosely and put it back for one to three days. Now your sourdough starter will enter a phase where it will rise and collapse and that is completely normal. That just means your sourdough is really active.
Now we will enter a stabilizing phase of your sourdough starter. This time I will feed it with a mix of 50% white flour and 50% wholemeal flour and we will do this seven days in a row that is to stabilize our row and make it more predictable. And this time I use hundred grams of flour and hundred grams of water and, of course the sourdough starter so get into a routine for the next seven days where you feed the sourdough starter with two tablespoons of sourdough starter and hundred grams of flour and hundred gram of water and the remaining of your sourdough starter, you can either give it to a friend or you can discard it After seven days sure sourdough starter should look something like this. And if you are interested in making 100% rye bread, you can of course make 100% rice which looks a little bit different but the principle is the same