I received my sourdough starter about 2 weeks ago, starting reviving as per instructions and it doubled in size in day 2 or 3. Since then I have been feeding every day or every second day along with discarding some of the original contents. The smell went from vinegary to nice and there has been minimal amounts of bubble activity but no doubling since the initial time. After discarding some starter, adding water and flour (a mix of rye and white organic) it has some small bubble activity, no rising, and the next day a layer of watery stuff appears on the top.
Yesterday I started following the recipe from the beginner's guide by taking a teaspoon of starter, adding water and flour and setting aside for 24 hours, BUT it has not risen, just stayed the same since I mixed the ingredients yesterday morning. Actually went the same as it does in the previous paragraph.
The recipe (Pane Francese 1) calls for 1/2 cup starter (so that means the starter I set aside yesterday should have doubled to include in this 'production'.
The question: What am I doing wrong? Does the starter have to double in size before every baking?
Thanks in anticipation and frustration!