Got this from Epicurious. Make sure to use flat soda. Let the soda stand at room temperature for at least 4 hours or overnight, this is important because you will need to boil the soda. The sauce can be prepared ahead of time (up to one week), cover and refrigerate. Bring to room temperature before using. The ribs can also be prepared up to the baking step one day ahead, keep covered in foil packets and refrigerate. Let stand at room temperature 1 hour before continuing with adding sauce. For the Dijon mustard with horseradish, since I couldn't find any, I just add about a teaspoon or two of horseradish to the Dijon mustard. If you can't barbecue the ribs on the last step, just broil them in the oven until the sauce has caramelized.