Add vinegar and salt to a small pot or sauce pan and heat to dissolve salt. Once salt is dissolved, let mixture cool and then stir in remaining ingredients. Set marinade aside.
(Note: My experience is that without the above step, the undissolved salt is not distributed equally throughout the marinade when you pour it over the ribs. The end result is that some portions of the meat are more or less salty than others).
Remove the tough membrane and excess fat on the underside of your ribs. Rinse ribs and pat dry.
Put ribs in a non-reactive container or large freezer bag. Pour marinade over the ribs and massage it into the meat.
Refrigerate ribs, meat side down, for 8 hours or overnight. Turn ribs occassionally.
When you're ready to cook your ribs, remove them from the refrigerator 30-45 minutes before placing them in the oven.
Preheat oven to 275°F.
Place ribs, bone-side down, in a covered roasting pan. Cook for about 3 to 3.5 hours.
Once ribs are done, remove from oven and let rest for 5 minutes before serving.
Recipe by Big Ken's BBQ at http://bigkensbbq.com/recipes/beef/oven-baked-beef-ribs/