I had a lot of problem recently with my levain miches after changing my regular flour brand for an other.
All my bread were overproofed. The proofing time seems to have changed with the new flour and I have to rely on the poke test to find the sweet spot where proofing is just right.
The problem is it's difficult to judge the result of the poke test just from reading about it. Could someone direct me to a good video showing how far to poke and how much spring back I should expect from the proofed dough ?