My best place is owned by a Turk, and the coffee there flows so rapidly that it is almost always really "just made."
At Panera's, the pressure-feeding coffee jugs have a ticket hung on the neck showing the time that jug was made. When it gets to be 30 minutes it has started to become sort of bitter.
In regard to ph, I did this somewhat on a lark. I didn’t set it up scientifically. I would have to do this over with better qc/qa.