I have been practising my Sourdough techniques for some months now, since a course at www.loafonline.co.uk with Tom Baker in the summer inspired me. Mostly I seem to be getting better, sometimes not.
This last weekend, I made a sponge on Friday night, added white flour and salt on Saturday, allowed it to bulk ferment for a couple of hours and then put the dough covered in the fridge overnight. I allowed the dough to warm up on Sunday morning ready for proving in bannetons. I left both loaves too long, so when they were transferred via a peel to the oven they slid down into a 2" high mass!
What did work though much better, was trying a Dan Lepard Mill loaf recipe from the Handmade Loaf. On first mixing the flours with the starter, the dough seemed to me to be very heavy. However over the next couple of hours of folding and gentle kneading, it became lighter. I transferred the dough into two bannetons for a couple of hours before baking at Gas Mark 9 for 10 minutes and Gas Mark 6 for a further 35 minutes.
The results you can see in the attached pictures. I was so pleased with the results, i had to share!