Nicely Spicy BBQ Sauce

Name: Nicely Spicy BBQ Sauce
Ingredients: 2 quarts tomato puree; 2 cups chopped onion; 3 cloves garlic; 1 tablespoon hot pepper flake; 1 ancho chile, stemmed and seeded and cut into 1/2-inch strips; 2 to 3 dry chipotle chiles, stemmed and seeded and cut into 1/2-inch strips; 1 teaspoon celery seed; 3 tablespoons salt; 10 whole peppercorns; 1/4 cup bourbon; 1 1/4 cups brown sugar, lightly packed; 1 1/3 cups apple cider vinegar; 1 teaspoon dry ginger; 1 tablespoon dry mustard; 1/2 cup maple syrup