Make the Sauce:
In a large pot, combine the tomato juice, tomato sauce, chopped onion, brown sugar, molasses, apple cider vinegar, allspice, ground mustard, salt, and black pepper. Simmer the sauce for 5 minutes, stirring occasionally.
Prepare Jars for Canning:
Prepare 7 quart jars by sterilizing them. Fill each jar with 1 1/2 cups of the prepared beans, then pour the sauce into the jars, leaving a 1-inch headspace at the top. Remove any air bubbles, and add additional sauce if needed. Wipe the rims of the jars clean.
Seal & Process the Jars:
Place the lids on the jars and screw on the rings until fingertip-tight. Process the jars in a pressure canner at 10 pounds of pressure for 90 minutes for quarts, or 75 minutes for pints.
