Preheat oven to 350°. In an ovenproof Dutch oven, cook bacon over medium heat until crisp, stirring occasionally. Remove with a slotted spoon; drain on paper towels. Cook and stir onion, yellow pepper, red pepper, garlic, chipotle pepper and pepper in bacon drippings until vegetables are tender. Remove from heat., Add beans and cooked bacon to Dutch oven; stir in barbecue sauce, vinegar and, if desired, liquid smoke., Bake, covered, 1 to 1-1/4 hours or until heated through. Freeze option: Freeze cooled beans in freezer containers. To use, partially thaw in refrigerator overnight. Heat through in a saucepan, stirring occasionally and adding a little water if necessary.