Group 2: for children weighing 15 - 25 kgs (33 - 55 lbs), roughly 4 to 6 years. Booster seats that only fit into Group 2 are less common. Most are group 2 and 3, or groups 1, 2 and 3. Groups 2 & 3: for children weighing 15 - 36 kg (33 - 79 lbs), roughly 4 to 11 years.
Broil the ribs for about 5 minutes, until the sugar in the dry rub is bubbling and the ribs are evenly browned. Bake the ribs: Set the oven to 300Â°F. Move the ribs to an oven rack in the middle of the oven. Roast for 2 1/2 to 3 hours for spare ribs or 1 1/2 to 2 hours for baby back ribs. Halfway through cooking, cover the ribs with aluminum foil to protect them from drying out.
Bake in the preheated oven until the ribs are very tender, 3 hours and 30 minutes to 4 hours. Carefully open each packet, and drain the drippings into a saucepan. You may only need the drippings from one packet.