Beginner sourdough maker here. I've tried 3 times now making sourdough and the dough tends to be weak after proofing. Twice with the Modernist's sour dough recipe (V3 p63), the dough flowed from the cold proofing (14 hrs) and I couldn't cut it with the lame because it was so sticky and fluid. However, when it baked it had a beautiful crumb will large pockets, the bread was flavorful and the crust was good. I can't seem to get a tight skin after the proofing.
(Recipe: 480g flour, 315g H20, 195g mature liquid levin (ie. 1 Starter, 3 flour, 3 H20), 10g wheat bran (I used wheat flour), 1 g Diastatic malt powder, 12g salt.) Autolyse, 4 hours, 6 folds, 14 hrs cold (fridge) ferment. Let warm up 1 hr and then bake.
Trying to debug the problem I am going down the track to see if the starter is good. After 9.5 hrs, it has doubled in size and passed the drop test (in water). The pH when I fed the starter was 5.41 and 9.5hrs later was 4.26. As an aside, the Modernist V3 p48 says a young levain will have a pH of 4.2-4.3 and can be used for leavening purposes. At most ripe it will be 3.8 to 3.9 and sour. So, I am assuming that the issue is not a faulty starter. The starter was made 50% King Arthur bread flour and 50% whole wheat.
Any ideas on my next steps to try and address the issue?