- Lightly bruise the rosemary, tarragon, thyme, and bay leaves to release their flavors.
- Put all the herbs and the fennel seeds into a large sterilized jar, then pour the vinegar.
- Seal the jar and shake well.
- Keep in a cool dark place for 2-3 weeks before using to allow their flavors to develop.
- Shake the jar occasionally.
- Line a funnel with a double layer of cheesecloth.
- Strain flavored vinegar through it into sterilized bottles, to within 1/8-inch of the tops.
- Seal the bottles and label.
- The vinegar is now ready to use.