Special equipment: a smoker and 1 1/2 cups applewood chips, soaked
Combine the cider vinegar, ketchup, sugar, molasses, mustard, soy sauce, tomato paste, Worcestershire sauce, red pepper flakes, salt and a pinch ground black pepper in a stainless steel saucepan over medium heat. Bring the mixture to a boil, reduce the heat and simmer for 10 minutes.
Remove from the heat and let cool before using. If not using immediately, pour it into a bowl or jar. Cover and refrigerate until needed.
Combine 1 quart water with the soy sauce, salt, sugar, honey and molasses in a large saucepan over medium heat. Bring the mixture to a boil, then remove from the heat and let cool. Stir in 1 gallon plus 3 quarts water. Pierce the meat with a boning knife in several places, then add the meat to the brine. Cover and refrigerate overnight.
Remove the meat from the brine, coat lightly with salt and pepper, and arrange in a smoker. Load 2 boxes filled with applewood chips into the smoker. Set the smoker at 250 degrees F and smoke for 8 hours.
Remove the meat from the smoker to a cutting board and shred when cool enough to handle. Arrange on a serving platter and serve with the BBQ sauce.
