I've cooked a lot of briskets and this is the first time I've had this happen to me. I cooked a 5lb flat yesterday like I normally do a 12lb packer. Put mustard slather on and then my rub and popped it in the smoker at 225 degrees until it hit 165 at which point I wrapped it and let it cook in foil until 195. I took it off the smoker and put in an ice chest for 1 hour until dinner time. I sliced it up and the smoke ring was great, the bark was great and juice was just rushing out. I went to take that first sample bit and the meat just tasted tuff. My question is do you think it was the meat or should I be questioning something else?