Mix sugar, salt, paprika, cumin, mustard, onion, garlic, and pepper in a small dish until well combined. Cut each rack of ribs in half so it's easier to handle. Sprinkle the seasoning over the meaty side if the ribs and rub with your finger tips to evenly distribute over all the meat. Set the ribs on a rimmed baking sheet, cover with plastic wrap and refrigerate 12-24 hours.
If using charcoal:
In a charcoal grill, arrange hot coals on only one side in the bottom of the grill to create a direct heat and indirect heat zone -- this will allow you to move the ribs over away from unmanageable flare-ups, if necessary. Start the ribs meat side down over direct heat to sear meat and caramelize the rub, 5-6 minutes. At this point you will want the lid on the grill but slightly ajar with an inch gap for good air circulation.
Once the meat side of the ribs brown, turn over and drizzle with a little oil. This will create some smoke, which you want. Continue to grill for another 20 minutes, rotating the ribs around over the hotter or cooler part of the fire to promote even browning. NOTE: Adding small amounts of oil that will slowly drip off the meat will provide some smoke if the ribs are lean (the object here is to create a steady, low stream of smoke to flavor the meat). If the oil causes a flare-up, placing the lid tightly on the grill and closing the vents should snuff it out (try not to spray it with water); when the flare up dies down, reopen the vents so the fire can breathe.
Once the ribs are browned and have a nice smoky aroma, remove from grill and place on a rack (in a single layer if possible) in a roasting pan. Pour beer in the bottom of the pan and cover with a tent of aluminum foil (don't let the foil touch the meat while cooking). Bake at 350° for 2 1/2 to 3 hours or until meat is very tender and loosening from the bone.
Transfer to a cutting board and allow to cool slightly so you can cut ribs between the bones with a sharp knife for individual servings. At this point, you can brush with sauce and return to the grill or place under the broiler for 5-6 minutes to caramelize the sauce and serve.
If using gas grill:
Start the ribs meat side down over medium-high heat to sear meat and caramelize the rub, 5-6 minutes. During these few minutes you can leave the lid closed, just keep an eye on it (turn the heat down if the meat is charring or flaring-up). NOTE: It can be harder to maintain a steady amount of smoke on a gas grill without causing unwanted flare-ups. Adding small amounts of oil that will slowly drip off the meat will provide some smoke if the ribs are lean (the object here is to create a steady, low stream of smoke to flavor the meat). The drip of fat should provide the smoke you need throughout the cooking process, just keep an eye on it. (See recipe notes for product to get more smoke flavor from a gas grill.)
Once the meat side of the ribs brown, turn over and drizzle with a little oil. This will create some smoke, which you want. Continue to grill for another 20 minutes, adjusting the heat up or down based on doneness.
Once the ribs are browned on both sides, remove from grill and place on a rack in a roasting pan (in a single layer if possible). Pour the beer in the bottom of the pan and cover with a tent of aluminum foil (don't let the foil touch the meat while cooking). Bake at 350°F for 2 1/2 to 3 hours or until meat is very tender and loosening from the bone.
Transfer to a cutting board and allow to cool slightly so you can cut ribs between the bones with a sharp knife for individual servings. At this point, you can brush with sauce and return to the grill or place under the broiler for 5-6 minutes to caramelize the sauce and serve.
Save those pan drippings for use as bouillon in other recipes. (See Notes)
Notes
Variation: Use ready-made Smoked Chile Pork Rub by Savoring Today instead of the spice ingredients listed. TIP: Once the ribs have been baked, you can freeze them and apply the sauce when ready to serve. To make gluten-free, use GF beer and barbecue sauce.To get more smoke flavor from a gas grill, I use Mo's Smoking Pouch Kit. It's easy to use and produces great results.
A note about the beer and pan drippings:
It's important to use beer or wine you enjoy drinking so that you'll also like the flavor of the pan drippings. I've used beer, wine, as well as a mix of either with broth to add flavor to the ribs, keep the pan from becoming too dry during baking and also flavor the pan drippings. If the pan has become dry, but not burnt, add some water to the pan to loosen the browned bits and gently stir the pan drippings with the water. If needed, add enough water to make the drippings pour-able. Skim the fat off with a spoon or pour into a fat separator to remove the fat. It's important to TASTE the drippings. It's okay if it tastes concentrated and slightly bitter or acidic -- this can boost other recipes.Once cooled, pour the drippings into a freezer zip-type bag and freeze flat. Break of pieces to add in place of bouillon to soups, sauces, and gravies. Note on the bag the flavors you tasted to help guide you when ready to use it.