Herbs that have low moisture content will dry better than those with high moisture content. For herbs with high moisture content freezing is the best way to keep them for future use. These herbs will retain more of their flavor when frozen: basil, parsley, cilantro, and chives. Herbs that are ideal for drying are: sage, mint, thyme, oregano, rosemary, and dill. The process is easy and is not time consuming.
DRYING FRESH HERBS
The first thing to remember is moisture will cause herbs to mold and rot so if you rinse them be sure to pat them dry and let them sit for a bit before tying them into bunches. Inspect the branches and remove any leaves that look unhealthy. Also take off the leaves on the bottom one inch of the branch. Bundle 4-6 branches together at the stem and tie them with a string or rubber band. The stems will shrink as they dry so be sure you have it tied tightly. Hang the bunch of herbs upside down in a dry, airy room (the laundry room or bathroom would not be a good choice) for about 2 weeks. They are ready when the leaves will crumble easily in your fingers. Always store the entire stem in an airtight container like a jar or zip lock bag because they will retain a lot more flavor if they are not crushed until you are ready to use them. Fresh dried herbs should keep for about a year. When they start to lose their color they are also losing flavor.
The best way to preserve herbs that have high water content is to freeze them. Moisture in the leaves will often cause the herb to mold before it becomes dry enough to store. While the leaves will become limp when frozen they will retain their flavor. Some of the herbs that are best frozen are basil, chives, cilantro, mint, and tarragon. Herbs that have been frozen will retain their potency for several months.
Wash and pat or spin dry the leaves and lay them on a cookie sheet that has been covered with parchment paper. Freeze over night and then store in an air-tight container in the freezer. If you plan to use the herbs in soup or stew chop the herbs and put them in ice cube trays, cover with water and freeze. Store the cubes in a plastic bag in the freezer.