That low temp is not safe. You want to cook the brisket low and slow like pork to an INTERNAL temp of 180*+ but the cooking temp is around 250*. It is the same principle as pulled pork and the results are similar. The internal collagenous fibers that make these cuts of meat tough break down when cooked low and slow. They do not break down when cooked above 300*--at that temp they "roast"--the proteins tighten up instead of tenderize.