Sourdough is such a popular bread now, probably because it is an easier bread to digest and reputed to be healthier for us. Most sourdough is made with white flour, but this recipe includes a mixture of rye and white flour. Using rye flour creates a denser texture than plain, though using all rye may be too strong for most pallets; a mixture of white flour and rye flour will give a more pleasant bread in both taste and texture. Like all sourdough's, you will need a sourdough starter, which takes a little time and some patience. Believe me, it is worth the effort for the dense, slightly, chewy bread with its pleasant 'sour' taste. See the notes below. The popular trend for making (and eating) sourdough bread is not looking likely to wane any time soon, thanks to celebrity bakers like paul hollywood. Before you begin make sure you have your starter ready and vigorous. This may require feeding for a few days if it has been dormant.