Herb-flavored vinegar is a delicious, pretty way to savor herbs long after the growing season is past. You don’t need any special equipment to make them; just reuse attractive glass bottles, so your tasty gifts will also be tasteful.
To make flavored vinegar, you will need bottles and cork stoppers to fit them (vinegar eats metal lids, even coated ones), enough good commercial vinegar to fill them, and fresh or dried herbs and spices. I like to use white-wine vinegar for delicate flavors like lemon balm, and organic apple-cider vinegar for more robust flavors like rosemary.
Wash and pat dry any fresh herbs—tarragon is a classic vinegar flavoring—and slide the whole leaves into the bottles, using a chopstick or wooden skewer as needed. Peeled garlic cloves and any kind of small peppers (slit down the side) are also nice choices for making flavored vinegar. Use about ½ cup of herbs per 2 cups of vinegar, or more if you want a very concentrated flavor. Fill the bottles with room-temperature vinegar and cork. Store in a cool, dark place. The flavor will continue to strengthen for 4 to 6 weeks. Use herb-flavored vinegars in salad dressings and marinades, splashed over veggies, or anywhere a recipe calls for vinegar or lemon juice.
To store vinegar longer, melt some beeswax (in a small steel can set in a pan of simmering water), and dip the corked end of the bottle into the wax to coat the top ¼ inch of the glass and the exposed cork. Let the wax harden, and repeat several times to build up a good coating. For extra-special gifting, drape a short length of ¼"- to ½"-wide ribbon over the top of the just-dipped bottle after the first dip. Hold the loose ends against the bottle neck and dip the top again, ribbon and all. The ribbon looks really classy, and makes it easy to remove the wax seal later.
You can also use your glass jars and corks for flavored oils. But placing herbs, garlic, peppers, fruit, and such, that contain even a trace of moisture into any oil is asking for trouble: The oil seals out the air and makes the perfect environment for botulism bacteria to thrive in the plant material. To be safe, you must store herb-flavored oils in the refrigerator and use them within a few weeks.
As an alternative, you can dry the herbs and other flavorings in a food dehydrator, or in the sun, until they are completely dry before adding them to a light-flavored organic olive oil or other cold-pressed oil. Add about 2 tablespoons of crushed dried herbs to 2 cups of oil.