My starter doesnt eat white flour
I posted on here a few months ago regarding issues with my starter. I've baked around 30 loaves between then and now and all have been failures. I'll attempt to add as much detail as possible to this post.
I take a time-lapse video of my starter during the day, keep it inside a proofing box, and feed it twice a day (1:8:5 starter:water:flour) I also occasionally measure pH, it's reliably around 5.5 after feeding and around 3.7 after it falls, typically around 4 at peak. I feed it rye flour, and sometimes a 50/50 mix of rye and whole wheat. It rises and falls predictably, tripling in volume at its peak (~6h after feeding kept at 78F), and falling at around 8 hours. I feed it 3 times on weekend days and only twice during the weekdays. Recently, out of frustration, I bought a starter (the KA starter), and was able to make good bread, which was enough incentive to keep trying. I've kept my starter alive purely out of stubbornness, but I can't get it to make anything good. Everything is under proofed, even after bulking for over 8h at 80C, at which point my gluten network starts to disintegrate and I end up with pancake batter.
Out of desperation, this morning I decided to feed it white KA AP flour instead of its usual Bob's organic dark rye. Because white flour can't hold as much water, I fed it a 1:6:5 ratio, instead of the usual 1:8:5 to reach a similar consistency. I've been watching it throughout the day and took a time-lapse. It's been 10 hours since I fed it and it hasn't grown at all. There seems to be marginal activity and a few small bubbles, but otherwise it's dead.
Do you guys have any idea why this is happening? why can my starter feed on rye very well, act predictably, smell good, etc, but isn't able to feed on white flour?
Thank you all in advance :)
EDIT: Link to pictures and videos of my starter and a few loaves of bread: https://drive.google.com/drive/folders/19aym23zFf8_aj-2V6PFI4yRzUTYIWhDO
Note: On videos, disregard the little container with the cloth, it's a 3 day-old starter I.