When making sourdough, do I use plain or self-raising flour? We recommend using High Grade Plain Flour, or Strong Bread Flour as the sourdough culture is a mix of culture and yeast.Self-raising flour has baking powder incorporated into it which is not required for sourdough. Related articles I’ve left my dough to rise for 48 hours instead of 24 but it isn’t rising as much in the second day as in the first. Have I done something wrong? How to Guide - Sourdough Can you use this sourdough kit with a bread maker? Does the sourdough culture contain dairy? Is the sourdough yeast gluten free?