The brining/marniating has "nothing" to do with how long it takes the chicken to cook ... it only has to do with "moistness". The temperature of your oil, and if you are over crowding the pan, has more to do with cooking time than anything.
Frying chicken in a pressure fryer takes about 8-9 minutes (after it reaches temp and pressure) - although I remember going to a KFC and they told me it would be about 30-mins ... so I wonder about how long it really takes. Actually, they were always out of original KFC and it was always going to take 30 minutes - so maybe the KFC in Golden, Colorado isn't a good example?
I was curious - so after I read your last post I made a trip to my two fave deep-fry chicken places and asked them ... Church's and Edmondson's - they deep fry "dark meat" pieces for about 15-mins, white for about 12. Of course I now have enough fried chicken to last me for a couple of days.
When Mom, Grandma, or my aunts "skillet fried" chicken ... it seems it took about 30-40 minutes or so
per batch. I don't think I've ever timed it - but I would guess that is about how long it takes me, too.
Candocook brought up a good point about the brining ... so after reading it I called and had a nice chat with a very nice lady who is the manager of a KFC near me. She was obviously doing her best not to laugh out loud about the ton of KFC myths ... but, she did confirm that KFC chicken is
NOT marinated before cooking. So ... that kind of makes this debate about Potassium in the marinade for original KFC kind of moot?