Leave beef brisket in its original packaging and place it in the coldest part of the refrigerator, where it will keep three to four days. For longer storage, wrap the meat in heavy-duty aluminium foil, freezer paper, or freezer bags. Beef brisket will keep six to twelve months in the freezer. Defrost the meat in the refrigerator, allowing 4 to 7 hours per pound for thick roasts, 3 to 5 hours per pound for thin cuts. Cook as soon as possible after defrosting.