Fresh herbs can get expensive if you’re buying them at the store, so I like to grow my own. I always make sure to use every last sprig. If you have leftover herbs, or a prolific plant that needs cutting back, you can dry herbs for your spice cupboard (see the sidebar “Spice Cupboard” in chapter 6, “Nuts”) or use them to flavor vinegar. Herb vinegars are made of two simple ingredients—vinegar and fresh herbs—and can be made in minutes. Subtle in flavor, herb vinegars impart an undertone of herb along with the tang of vinegar. They can be used in salads and vinaigrettes.
Use fresh healthy sprigs and distilled white vinegar for the best results. Any herb can work—try mint, lemon balm, basil, or tarragon. Use two sprigs of herb for every cup of vinegar. Add the sprigs directly to prepared jars. (Wash and sterilize jars for 10 minutes in a hot water bath before using.) Heat the vinegar until just beginning to boil and pour over the herbs, leaving a bit of head space. Store the vinegar in a cool, dark place for three to four weeks, checking the flavor after two weeks. When the flavor is to your liking, strain and discard the herbs and store the infused vinegar in a cool, dark cupboard. Use glass containers that can be sealed with a lid or cork.
Herb vinegars will keep for three months, longer if refrigerated. Be mindful of any mold or fermentation bubbles—this means the batch is spoiled and should be thrown out. As vinegar has a high acid content, there is no risk of botulism; mold and yeast are the two culprits of spoilage.