As you approach the hour per pound point you will want to start taking the temperature of your brisket. You will need to take the temperature in several places, aiming for a thick piece of meat. You should be able to feel the difference between the fat and the meat. By this point the fat is about as solid as warm butter. The meat on the other hand should give you some resistance as you insert the probe.
You are looking for an internal temperature above 175 degrees F. This is beyond well done for beef, but still too cool for a good brisket. Ultimately you want a temperature above 185 degrees F, but when you get to 175 it is time to wrap your brisket.
