Oven or the unheated side of a grill or bbq). Beef ribs, including short ribs) at 325F take about 3-4 hours til they are tender. Pork country style ribs take about 2.5-3 hours. St. Louis style ribs, about 2 hours, and pork baby-back ribs, about 1.5-2 hours. This all depends on the size of the ribs, and how well they are trimmed.