Eastern North Carolina BBQ Sauce, A La Egerton

Sauces

2 cups cider vinegar
1 tablespoon peppercorns
1 teaspoon celery seed
1 teaspoon salt
1 tablespoon red pepper flakes
1 onion; finely chopped
1 cup water

Combine in a large saucepan. Bring to a boil, reduce heat, and simmer uncovered for an hour. Strain to remove the peppercorns if you like.