Trim the spareribs, if necessary, and rub both sides of the ribs with the dry rub, working it into the meat. Put the ribs in a shallow glass or ceramic dish, cover, and set aside at room temperature for no longer than 30 minutes, or refrigerate for up to 24 hours. Alternatively, enclose the ribs in a sealable plastic bag and refrigerate.
Prepare a charcoal or gas grill, arranging the coals for indirect cooking. Lightly spray the grill rack with vegetable cooking spray. The coals should be hot.
Set the ribs, meat side down, over the hottest part of the fire and sear for about 10 minutes until there are defined grill marks on the meat. Transfer the ribs to the cooler part of the grill, cover, and turning the ribs every 15 to 20 minutes, cook for about 1 1/2 hours. If using a charcoal grill, add fresh coals to maintain the heat at medium; if using a gas grill, turn the heat to medium on the burner away from the meat -- turn off the burner under the meat. Cut the ribs between the bones and serve with sauce on the side.
Mix the ingredients together in a glass jar or bowl. Cover and shake to mix. Refrigerate until ready to use.