I don't understand why this happened. I prepared the dough and baked it same as usual.
I didn't score deeply enough to break up the inner layers of the dough but the layers were torn so badly.
Any helps would be appreciated.
It looks like you have major bursts there and, if so, that suggests UNDERproofing. Was the dough proofed at a lower temperature than normal? Is the yeast old or the leaven not active enough? Give us a bit more clue of your recipe and processes and we can - hopefully - be more helpful.
They look underproved.
(Or) Have you changed flour supply recently?
Thank you for your helps, Ruralidle and HVHB.
I have been thinking that my starter looks a little bit less active but I had no idea this is related to the bad bursting.
I will give more attention on the starter and try again.
Yes, I have changed to the flour which has less protein .
Yesterday I ordered previous flour.
And how about hydration ? My normal recipe was 400g of flour, 150g of starter ( 100% hydration ), 240g of water .
This time, I cut down the water to 220g to make a little stiffer dough for better shaping work.
Did less water influence fermentation process resulting in under proof ? ( I did give the dough same proofing time, 2 hours. )
Generally, if I recall correctly, the lower the hydration the longer proofing takes. Your initial hydration works out at 66.3% and after your revision is 62.1%. At that level you could have slowed proofing noticeably. I rarely use less than 65% hydration.
I have to agree with Ruralidle about too low an hydration. I have seen this often before and although underproofing does cause bursting as suggested, it also causes shape distortion and irregular bursting. Your loaves seem to have a good symetrical shape however and the bursting shown suggests too tight a dough. I too wouldn't use less than 65%, often as high as 75% with excellent results as long as the dough is adequately developed.