Loaves busting out too much, please help!
My loaves keep busting out at the sides. I am;
1. Using organic stone-ground flours, sometimes white, sometimes white/brown mix (2.5kg total flour weight)
2. With a poolish ferment 7-8 hrs before (poolish = half tsp of yeast, 2 tsp of cane sugar, 300g flour, 600ml water)
3. I steam oven well at 250c for 7 mins then drop heat to 150 c for 20 mins, then 200 c for last 10 mins for brown.
4. I slash just before putting in oven. They spring well and get nice volume and a nice crust, but then just bust out at the sides.
What can I try other than;
1. Reducing the initial heat.
2. Reducing the 250c to 3 or 5 mins.
3. Glazing with egg white and/or water.
4. lengthening the proof time.
5. Kneading more/less
Any other pointers