Combine all ingredients except for ribs and oil in a bowl. Rub ribs all over with oil and smear with seasonings, putting most on meaty side. Chill airtight at least 4 and up to 24 hours; let stand at room temperature during last hour. Meanwhile, scrunch each of 5 (1 1/2 ft.) sheets of foil into a log about 9 in. long; set aside.
Prepare a grill for low (250° to 300°) with a burner turned off (for gas) or coals pushed to sides of firegrate (for charcoal) to make an indirect-heat area. Put a 9- by 13-in. pan in the indirect-heat area.
Set ribs with bone tips upright over drip pan, arranging foil logs between ribs to hold them up. Grill, covered, until meat is very tender when pierced and shrinks back 1/2 in. from tips of bones, 1 3/4 to 2 1/4 hours.
Transfer ribs to a rimmed baking sheet and cover with foil. Let rest about 10 minutes, cut between bones, and serve.
Secrets for Fantastic Ribs:
USE PORK SPARERIBS AND BEEF SHORT RIBS. More generously marbled than pork baby back ribs, country-style spareribs, or regular beef ribs, they're noticeably more juicy and flavorful.
TRIM SPARERIBS ST. LOUIS-STYLE. Meaning, trim them into a tidy, rectangular shape that cooks evenly. Ask a butcher to trim them, or do it yourself: On the bony side, trim the flap of meat from the center, flush with the bones. Then cut the rack lengthwise between the 4- to 5-in.-wide rib section and the chewy skirt (above). Save scraps for soup.
REMOVE THE MEMBRANE. Pork spareribs have a membrane on the underside that can shrink up and make the meat cook unevenly. It's easy to remove: Slide the tip of a meat thermometer under the membrane at one end to loosen an edge. Pull off membrane with a paper towel (it may come off in pieces) while holding the rack down with your other hand.
Setting Up Your Grill:
MASTER THE ART OF INDIRECT HEAT. This allows the ribs to cook long and slow, so they become extremely tender and rendered of much of their fat. Then brown them over the direct-heat part of the fire.
If using gas, put a drip pan in place under one part of the cooking grate (the indirect-heat area), then light only the burner or burners on the rest of the grill (the direct-heat area).
If using charcoal, ignite 50 briquets in a chimney, then bank coals on opposite sides of firegrate, leaving a cleared area in the middle. Set a drip pan in the cleared area. Let coals burn down to the temperature specified in the recipe. To maintain the temp during cooking, add 5 briquets to each mound of coals about every 30 minutes, starting when ribs go on grill; if fire gets too hot, partially close vents under grill and on lid.
*Buy ground fennel seeds, or pound seeds with a mortar and pestle.