My loaf is at 73% hydration and a 6 hour bulk ferment at around 70F. I did one stretch and fold, one lamination, and 4 coil folds. I did something a little different this time where I added my starter and my salt at the same time and then slap and folded. I usually add the salt 30 minutes after I add in the levain but I decided to add it at the same time and ended up with this crumb.
What is the cause of these giant holes?
Google , or use the TFL search box, for that.
In a word: Underfermentation.
Tom