- Soak the fillets in a bowl of cold water in the refrigerator for 12 to 24 hours.
- Change water twice.
- To make the pickling solution, combine water, vinegar, seasonings and sugar in a saucepan; bring to a boil.
- Stir to dissolve sugar; let cool.
- Rinse the fillets with cold water and pat dry with paper towels.
- Cut in 1-inch pieces removing bones.
- Peel and slice onion.
- Separate slices into rings.
- Arrange herring and onion rings in alternate layers in sterilized jars.
- Cover with pickling solution and cap.
- Refrigerate at least 3 days before serving.
- The herring will keep up to 3 weeks refrigerated.