1. In a 1-pint canning jar, using 2 cups traditional black-eyed peas, alternate layers of peas with oregano, cumin seeds, and serrano chiles. In a second jar, layer 2 cups peas with wax peppers and mustard seeds. In a third jar, layer remaining 2 cups peas with chile peppers, red-pepper flakes, and fennel seeds. Set aside.

2. In a saucepan, combine vinegar and salt. Heat until mixture just comes to a boil. Pour 3/4 cup vinegar mixture over each jar of peas to cover all layers. Seal jars. When mixture cools to room temperature, refrigerate at least a week and up to a month.