I have made a couple really good briskets in the past couple months so I figured I would smoke one for the 4th. I picked one out at costcoand it looked like it had a good amount of fat on it like the others. I smoked it for 12 hours 2-4 hours more than the other 2 i got it up to 190 and pulled it wrapped it in foil and blankets and put it in the cooler. An hour later i started to slice it and there was no fat to be seen. when I took a bite it was as tough as old shoe leather. My question would be is this from there not being enough fat or not smoking it long enough?